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Sample records for absorption root

  1. Economic strategies of plant absorptive roots vary with root diameter

    Science.gov (United States)

    Kong, D. L.; Wang, J. J.; Kardol, P.; Wu, H. F.; Zeng, H.; Deng, X. B.; Deng, Y.

    2016-01-01

    Plant roots typically vary along a dominant ecological axis, the root economics spectrum, depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root economic strategies differ with increasing root diameter. To test this hypothesis, we used seven plant species (a fern, a conifer, and five angiosperms from south China) for which we separated absorptive roots into two categories: thin roots (thickness of root cortex plus epidermis perspective on our understanding of the root economics spectrum.

  2. PHOTOSYNTHESIS AND ABSORPTION OF MINERAL NUTRIENT IN TOMATO PLANTS UNDER VARIOUS ROOT ZONE TEMPERATURE AND LIGHT CONDITIONS

    OpenAIRE

    Kosobrukhov, A. A.; Bagnavets, E. A.; Semenova, N. A.

    1988-01-01

    Effect of various light and temperature regimes in the root zone on the light stage of photosynthesis, gas exchange, growth processes and absorption of mineral nutrients by tomato plants were studied. Optimum temperatures for dry matter accumulation and absorption of mineral nutrients were found to be shifted when the irradiation condition were changed. A shift of optimum temperatures for dry matter accumulation and absorption of mineral nutrients was found to be due to a change in irradiatio...

  3. Pattern of zinc-65 incorporation into soybean seeds by root absorption, stem injection, and foliar application

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A.; Weaver, C.M. (Purdue Univ., West Lafayette, IN (USA))

    The pattern of {sup 65}Zn incorporation into soybean seeds of plants grown hydroponically and intrinsically labeled with {sup 65}Zn by root absorption, stem injection, and foliar application was studied. Stem injection resulted in the greatest (64.5% of dose) accumulation of {sup 65}Zn while incorporation of {sup 65}Zn through root absorption was the least (23.4%) and through foliar application was intermediate (37.5%). Regardless of the labeling techniques, approximately 40-45% of the seed {sup 65}Zn was associated with the subcellular organelles. The pattern of zinc incorporation did not change appreciably as a result of the labeling technique. The major portion of the soluble zinc was not associated with the major proteins (11S and 7S) of soybeans but either was free or was associated with very low molecular weight amino acids, peptides, or their complexes with phytic acid. Zinc in soybean seems to be ionically bound, and this association is affected by the pH of the extracting buffer.

  4. Radiocaesium and radiostrontium uptake by turnips and broad beans via leaf and root absorption

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Paniagua, J.M.; Rufo, M. [Departamento Fisica, Facultad de Veterinaria, E. Politecnica - Uex, Avda. Universidad s/n, Caceres, (Spain); Sterling, A. [Consejo de Seguridad Nuclear, Madrid (Spain); Barandica, J. [Departamento Ecologia, F. De Biologia, UCM Madrid, Madrid (Spain)

    1999-03-01

    One of the immediate consequences of massive radioisotope release into the atmosphere is contamination of the biosphere. This contamination can affect plants either by direct deposition onto the leaves, or by contaminating the soil followed by absorption by the roots. Knowledge of the efficacy of the two routes of radionuclide incorporation into the food chain is fundamental to understanding the mechanisms by which radioactive contamination reaches man. The present work analyzes the incorporation of {sup 134}Cs and {sup 85}Sr via root and leaf uptake into the parts consumed by man, for two very different crops: turnip (Brassica napus) and broad bean (Vicia faba). The root uptake studies consider the available soil fraction for these two radionuclides, and indicate greater availability for {sup 85}Sr than for {sup 134}Cs which is fixed rapidly in the soil. For the study of leaf uptake, leaves were contaminated at three different stages of plant growth; the results indicate an inverse dependence of the transfer coefficients on the time elapsed from the moment of the contamination to harvesting of the edible parts.

  5. Effects of arbuscular mycorrhizal fungi on leaf solutes and root absorption areas of trifoliate orange seedlings under water stress conditions

    Institute of Scientific and Technical Information of China (English)

    WU Qiangsheng; XIA Renxue

    2006-01-01

    The effects of the arbuscular mycorrhizal (AM)fungus Glomus mosseae on plant growth,leaf solutes and root absorption area of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were studied in potted culture under water stress conditions.Inoculation with G.mosseae increased plant height,stem diameter,leaf area,shoot dry weight,root dry weight and plant dry weight,when the soil water content was 20%,16% and 12%.AM inoculation also promoted the active and total absorption area of root system and absorption of phosphorus from the rhizosphere,enhanced the content of soluble sugar in leaves and roots,and reduced proline content in leaves.AM seedlings had higher plant water use efficiency and higher drought tolerance than non-AM seedlings.Effects of G.mosseae inoculation on trifoliate orange seedlings under 20% and 16% soil water content were more significant than under 12% soil water content.AM infection was severely restrained by 12% soil water content.Thus,effects of AM fungi on plants were probably positively related to the extent of root colonization by AM fungi.The mechanism of AM fungi in enhancing drought resistance of host plants ascribed to greater osmotic adjustment and greater absorption area of root system by AM colonization.

  6. [Nitrogen absorption and allocation in cotton plant under effects of double-cropping wheat and cotton root mass].

    Science.gov (United States)

    Wang, Ying; Zhou, Zhiguo; Chen, Binglin; Meng, Yali; Shu, Hongmei

    2006-12-01

    By the methods of 15N-foliar feeding and 15N dilution, a pot experiment of double-cropping wheat and cotton was conducted to study the nitrogen absorption and allocation in cotton plant under effects of wheat and cotton root mass. Three treatments were installed, i.e., no separation of wheat and cotton roots (treatment I), separation with nylon net (treatment II), and separation with plastic film (treatment III). The results showed that both the competition of 15N absorption between wheat and cotton root, and the translocation of absorbed 15N from wheat root to cotton were existed in the wheat-cotton double-cropping system. The absorbed 15N by cotton root was mostly allocated in aboveground part, and less in root. The aboveground part of cotton had the highest N utilization rate (NUR) in treatment I and the lowest one in treatment III, but the Ndff was lower in treatment I than in treatments II and III. At the early flowering stage of cotton when wheat was harvested and its straw was amended in situ, the absorbed nitrogen by cotton was mainly from the applied 15N, but not from the amended wheat straw. The allocation of absorbed 15N in different organs of cotton was quite different, being much higher in reproductive organs than in other organs. The biomass of cotton plant was also higher in treatment I than in treatments II and III.

  7. Evaluation of absorption of radionuclides via roots of plants at different growth stages

    Energy Technology Data Exchange (ETDEWEB)

    Ambe, Shizuko [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1999-03-01

    For the environmental risk assessment of radionuclides and toxic elements which were released by nuclear power plants and factories, the absorption of trace elements by plants has been studied by a multitracer technique. The selective absorption coefficient, which is a parameter of an uptake model of radionuclides by plants, was determined for various radionuclides. The selective absorption coefficients of some elements varied greatly in experimental runs. Therefore, the selective absorption coefficients of radionuclides by komatsuna at different growth stages were determined. Moreover, the soil-to-plant transfer of radionuclides in komatsuna at different growth stages was studied. Extraction of the radionuclides from the soil was carried out in order to study the correlation between the transfer factor and the aging effect of the radionuclides in soil. The effect of soil acidity on the absorption of radionuclides in soybean and tomato was studied using the plants at different growth stages. (author)

  8. Absorption of Nickel, Chromium, and Iron by the Root Surface of Primary Molars Covered with Stainless Steel Crowns

    Directory of Open Access Journals (Sweden)

    David Keinan

    2010-01-01

    Full Text Available Objective. The purpose of this study was to analyze the absorption of metal ions released from stainless steel crowns by root surface of primary molars. Study Design. Laboratory research: The study included 34 primary molars, exfoliated or extracted during routine dental treatment. 17 molars were covered with stainless-steel crowns for more than two years and compared to 17 intact primary molars. Chemical content of the mesial or distal root surface, 1 mm apically to the crown or the cemento-enamel junction (CEJ, was analyzed. An energy dispersive X-ray spectrometer (EDS was used for chemical analysis. Results. Higher amounts of nickel, chromium, and iron (5-6 times were found in the cementum of molars covered with stainless-steel crowns compared to intact molars. The differences between groups were highly significant (<.001. Significance. Stainless-steel crowns release nickel, chromium, and iron in oral environment, and the ions are absorbed by the primary molars roots. The additional burden of allergenic metals should be reduced if possible.

  9. Isolation and expression analysis of novel silicon absorption gene from roots of mangrove (Rhizophora apiculata) via suppression subtractive hybridization.

    Science.gov (United States)

    Sahebi, Mahbod; Hanafi, Mohamed M; Abdullah, Siti Nor Akmar; Rafii, Mohd Y; Azizi, Parisa; Nejat, Naghmeh; Idris, Abu Seman

    2014-01-01

    Silicon (Si) is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots' cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein.

  10. [Alleviated affect of exogenous CaCl2 on the growth, antioxidative enzyme activities and cadmium absorption efficiency of Wedelia trilobata hairy roots under cadmium stress].

    Science.gov (United States)

    Shi, Heping; Wang, Yunling; Tsang, PoKeung Eric; Chan, LeeWah Andrew

    2012-06-01

    In order to study the physiological mechanism of exogenous calcium on the toxicity of heavy metal cadmium (Cd) to Wedelia trilobata hairy roots, the effects of Cd alone, and in combination with different concentrations of Ca on growth, contents of soluble protein and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD), Cd2+ absorption in W. trilobata hairy roots were investigated. Cd concentrations lower than 50 micromol/L enhanced the growth of hairy roots, while concentrations higher than 100 micromol/L inhibited growth, making the branched roots short and small, and also turning the root tips brown, even black. In comparison with the control (0 micromol/L Cd), the soluble protein content in hairy roots was found to increase when cultured with 10-50 micromol/L Cd, and decrease when exposed to a cadmium concentration higher than 100 micromol/L Cd. In addition, the activities of POD and SOD activity and MDA content were significantly higher than the control. Compared to the control (hairy roots cultured without 10-30 mmol/L Ca), 100 micromol/L Cd or 300 micromol/L Cd in combination with 10-30 mmol/L Ca resulted in increased growth, causing the main root and secondary roots thicker and also an increase in soluble protein content. On the contrary, MDA content and POD and SOD activities decreased. Quantitative analysis by Atomic Absorption Spectrophotometry showed that W. trilobata hairy roots can absorb and adsorb heavy metal Cd in the ionic form of Cd2+. The maximum content of Cd2+ absorbed by the hairy roots was obtained with a concentration 100 micromol/L Cd2+ while that of Cd2+ adsorbed by hairy roots was achieved with a concentration of 300 micromol/L Cd2+. The exogenous addition of 10-30 mmol/L Ca2+ was found to reduce the absorption, adsorption of Cd2+ and the toxicity of Cd significantly. This reduction in toxicity was caused by the reduction in the absorption of Cd and decreasing the lipid peroxidation through regulating the

  11. 莲藕对油脂和胆固醇吸附作用研究%Absorptive Properties of Lotus Root for Fat and Cholesterol

    Institute of Scientific and Technical Information of China (English)

    李莲花; 李锐莉

    2013-01-01

    This study used the colorimetric method to determine the absorptive properties of different morphological parts of lotus root for the unsaturated fatty acid, saturated fat and cholesterol. The results showed that the three different morphological parts of lotus root had roughly the same adsorptive ability for fat, but the morphological lower end possessed the strongest adsorptive ability for unsaturated fatty acid, while the morphological upper end possessed the strongest adsorptive ability for saturated fatty acid. Lotus root had the strongest adsorptive ability for cholesterol when the adsorption time was 150 min and the dosage of lotus root was 0.1 g. Lotus root had a high absorptive capacity for fat and cholesterol, and it was an excellent health-care vegetable.%  用比色法测定了莲藕不同部位对不饱和脂肪酸、饱和脂肪酸以及胆固醇的吸附能力.研究结果表明,莲藕的形态学上端、中部、下端对油脂的吸附能力大致相同,但对不饱和脂肪酸的吸附以形态学下端为最大,对饱和脂肪酸的吸附以形态学上端为最大;当吸附时间为150 min、用量为0.1 g时,莲藕对胆固醇的吸附能力最强.莲藕对油脂和胆固醇均具有一定的吸附能力,属于一种优质的保健蔬菜品种.

  12. Isolation and Expression Analysis of Novel Silicon Absorption Gene from Roots of Mangrove (Rhizophora apiculata via Suppression Subtractive Hybridization

    Directory of Open Access Journals (Sweden)

    Mahbod Sahebi

    2014-01-01

    Full Text Available Silicon (Si is the second most abundant element in soil after oxygen. It is not an essential element for plant growth and formation but plays an important role in increasing plant tolerance towards different kinds of abiotic and biotic stresses. The molecular mechanism of Si absorption and accumulation may differ between plants, such as monocotyledons and dicotyledons. Silicon absorption and accumulation in mangrove plants are affected indirectly by some proteins rich in serine and proline amino acids. The expression level of the genes responsible for Si absorption varies in different parts of plants. In this study, Si is mainly observed in the epidermal roots’ cell walls of mangrove plants compared to other parts. The present work was carried out to discover further information on Si stress responsive genes in Rhizophora apiculata, using the suppression subtractive hybridization technique. To construct the cDNA library, two-month-old seedlings were exposed to 0.5, 1, and 1.5 mM SiO2 for 15 hrs and for 1 to 6 days resulting in a total of 360 high quality ESTs gained. Further examination by RT-PCR and real-time qRT-PCR showed the expression of a candidate gene of serine-rich protein.

  13. Differential gene expression in Rhododendron fortunei roots colonized by an ericoid mycorrhizal fungus and increased nitrogen absorption and plant growth

    Directory of Open Access Journals (Sweden)

    Xiangying Wei

    2016-10-01

    Full Text Available Ericoid mycorrhizal (ERM fungi are specifically symbiotic with plants in the family Ericaceae. Little is known thus far about their symbiotic establishment and subsequent nitrogen (N uptake at the molecular level. The present study devised a system for establishing a symbiotic relationship between Rhododendron fortunei Lindl. and an ERM fungus (Oidiodendron maius var. maius strain Om19, quantified seedling growth and N uptake, and compared transcriptome profiling between colonized and uncolonized roots using RNA-Seq. The Om19 colonization induced 16,892 genes that were differentially expressed in plant roots, of which 14,364 were upregulated and 2,528 were downregulated. These genes included those homologous to ATP-binding cassette transporters, calcium/calmodulin-dependent kinases, and symbiosis receptor-like kinases. N metabolism was particularly active in Om19-colonized roots, and 51 genes were upregulated, such as nitrate transporters, nitrate reductase, nitrite reductase, ammonium transporters, glutamine synthetase, and glutamate synthase. Transcriptome analysis also identified a series of genes involving endocytosis, Fc-gamma R-mediated phagocytosis, glycerophospholipid metabolism, and GnRH signal pathway that have not been reported previously. Their roles in the symbiosis require further investigation. The Om19 colonization significantly increased N uptake and seedling growth. Total N content and dry weight of colonized seedlings were 36.6% and 46.6% greater than control seedlings. This is the first transcriptome analysis of a species from the family Ericaceae colonized by an ERM fungus. The findings from this study will shed light on the mechanisms underlying symbiotic relationships of ericaceous species with ERM fungi and the symbiosis-resultant N uptake and plant growth.

  14. Correlation between relative growth rate and specific leaf area requires associations of specific leaf area with nitrogen absorption rate of roots.

    Science.gov (United States)

    Osone, Yoko; Ishida, Atsushi; Tateno, Masaki

    2008-07-01

    Close correlations between specific leaf area (SLA) and relative growth rate (RGR) have been reported in many studies. However, theoretically, SLA by itself has small net positive effect on RGR because any increase in SLA inevitably causes a decrease in area-based leaf nitrogen concentration (LNCa), another RGR component. It was hypothesized that, for a correlation between SLA and RGR, SLA needs to be associated with specific nitrogen absorption rate of roots (SAR), which counteracts the negative effect of SLA on LNCa. Five trees and six herbs were grown under optimal conditions and relationships between SAR and RGR components were analyzed using a model based on balanced growth hypothesis. SLA varied 1.9-fold between species. Simulations predicted that, if SAR is not associated with SLA, this variation in SLA would cause a47% decrease in LNCa along the SLA gradient, leading to a marginal net positive effect on RGR. In reality, SAR was positively related to SLA, showing a 3.9-fold variation, which largely compensated for the negative effect of SLA on LNCa. Consequently, LNCa values were almost constant across species and a positive SLA-RGR relationship was achieved. These results highlight the importance of leaf-root interactions in understanding interspecific differences in RGR.

  15. 不同影像学技术对正畸治疗中牙根吸收评估的特点分析%Analysis of characteristics of root absorption assessment in orthodontic treatment with different medical imaging technology

    Institute of Scientific and Technical Information of China (English)

    张茹; 樊永杰

    2015-01-01

    正畸治疗中对牙根吸收的评估在正畸学的研究中起着很重要的作用。随着现代医疗检测设备的发展,准确性较高的牙根吸收度的测量技术相继问世和推广,牙根吸收的研究取得了较大的进展。本文就现有临床采用的根尖周片、曲面体层片、头颅侧位片、多层螺旋CT、锥形束CT等主要影像学技术检测牙根吸收的特点作一综述。%The assessment of root absorption in orthodontic treatment plays a very important role in the study of orthodontics .With the devel-opment of modern medical testing equipments, the high-accuracy measuring technology of evaluating root absorption has been available and gener-alized.More progress has been made in the research on root absorption.This paper tries to discuss the characteristics of root absorption detection applied clinically with the main imaging technology which includes periapical radiograph, panoramic radiograph, lateral cephalogram, multi-slice spiral computed tomography, cone beam computed tomography ( CBCT) and so on.

  16. Characteristics of Potassium-Enriched, Flue-Cured Tobacco Genotype in Potassium Absorption,Accumulation,and In-Ward Potassium Currents of Root Cortex

    Institute of Scientific and Technical Information of China (English)

    YNAG Tie-zhao; LU Li-ming; XIA Wei; FAN Jin-hua

    2007-01-01

    This study was to investigate the main traits of potassium-enriched,flue-cured tobacco genotypes related to potassium absorption,accumulation,and in-ward potassium currents of the root cortex.Hydroponic methods,K+-depletion methods,and patch-clamp,whole-cell recordings were conducted to study the accumulation of dry matter and potassium in different organs,and to measure potassium absorption and dynamic and in-ward potassium currents in potassium-enriched,fluecured tobacco genotypes.The average dry weights of leaves and whole plant of potassium-enriched,flue-cured tobacco genotype ND202 were 10.20,and 14.85g,respectively,higher than JYH(8.50 and 13.11g,respectively)and NC2326(8.39 and 12.72g,respectively),when potassium concentration in the solution ranged from 0.1 to 50mmol L-1.Potassium accumulation in the leaves of ND202 was 18.6% higher than JYH and 34% higher than NC2326 when potassium concentration in the solution was superior to 0.5mmol L-1.The Vmax(the maximum velocity)of ND202 was 118.11μmol FW g-1h-1,obviously higher than that of JYH(58.87 μmol FW g-1 h-1)and NC2326(64.40μmol FW g-1 h-1).In the in-ward potassium currents,the absolute value of current density(pA/pF)of ND202 was 60,higher than that of JYH(50)and NC2326(40).Potassium concentration in leaves,Vmax and in-ward potassium currents,could be used to screen potassium-enriched,flue-cured tobacco genotypes.

  17. Orthodontic treatment in the relationship between tooth and root absorption of clinical studies%探讨正畸治疗中拔牙与牙根吸收关系

    Institute of Scientific and Technical Information of China (English)

    赵彦文

    2015-01-01

    ObjectiveTo study the analysis of the orthodontic treatment of the relationship between tooth and root absorption.methodsFrom January 2012 to January 2015, were accepted our dental orthodontic treatment of patients with a total of 200 cases included in the study, grouped according to whether a tooth out, observed two groups of patients receiving orthodontic treatment before and after root absorption differences. ResultsTooth, tooth group patients received orthodontic treatment before root absorption, by contrast, no signiifcant differences (P>0.05), no statistical signiifcance; Tooth group of patients after orthodontic treatment, root absorption is obviously higher than that of the tooth extraction group, there was a signiifcant difference compared (P<0.05), with statistical significance.ConclusionIn the orthodontic treatment can accentuate tooth root absorption, whether during orthodontic treatment need tooth extraction and identiifcation of high-risk groups is clinical research further.%目的:分析正畸治疗中拔牙与牙根吸收的关系。方法选择2012年1月~2015年1月我院口腔科收治的接受正畸治疗患者200例作为研究对象,根据是否拔牙分为拔牙组和非拔牙组,对比观察两组患者接受正畸治疗前、后牙根吸收情况方面的差异。结果拔牙组、非拔牙组患者接受正畸治疗前牙根吸收情况对比,差异无统计学意义(P>0.05);拔牙组患者接受正畸治疗后,牙根吸收情况明显高于非拔牙组,差异有统计学意义(P<0.05)。结论在正畸治疗中拔牙会加重牙根吸收,正畸治疗期间是否需要拔牙以及对高危人群的识别是临床进一步研究重点。

  18. 硝态氮(NO-3)对水稻侧根生长及其氮吸收的影响%Effects of Nitrate on the Growth of Lateral Root and Nitrogen Absorption in Rice

    Institute of Scientific and Technical Information of China (English)

    王小兵; 吴平; 胡彬; 陈青爽

    2002-01-01

    Lateral root is primary organ for plant to explore and utilize soil nutrient efficiently.The development of lateral roots (LR) is controlled by both genetic factors and nutrient status in environment.To investigate the effects of nitrate (NO-3) on rice lateral root growth and nitrogen (N) uptake efficiency under upland condition,three treatments,including root-split culture and whole plant culture in N sufficient and deficient conditions,were used in a vermiculite culture experiment.Root-split treatment showed that the growth of lateral roots was stimulated by localized nitrate supply.However,in whole plant culture,elongation of lateral roots was induced by NO-3 deficiency.The effects of NO-3 on rice lateral root growth were genotype-dependent.Similar N concentration,soluble sugar concentration and N content in shoot were observed in both root-split treatment and whole plant culture under NO-3 sufficient condition,suggesting that the nitrogen requirement for rice normal growth could be satisfied with only half of roots supplied with NO-3.In the root-split treatment,N uptake was positively correlated with the average of lateral root length (ALRL) in NO-3-supplied side,suggesting that the ALRL is important for rice root N uptake in the environment where the nitrogen nutrient is limiting factor.No significant correlation was observed between N uptake and ALRL in whole plant culture under N sufficient condition,which implies that the length of lateral roots may not be the main factor to determine the rice root N uptake in nutrient-rich zone.Morphological and metabolic evidence in this study provided some prospects for genetic improvement of root system characters to improve the efficiency of nutrient absorption in rice.%侧根是植物吸收利用土壤养分的重要器官,其生长发育受内部遗传因子和外部环境矿质养分的影响.通过琼脂分层培养发现:局部供应NO-3可以诱导水稻( Oryza sativa L.)主根或不定根上侧根的生

  19. Inductively coupled plasma-emission spectroscopy and atomic absorption for the use of elemental analysis of a root canal after lasing with a holmium:YAG laser.

    Science.gov (United States)

    Deutsch, Allan S; Cohen, Brett I; Musikant, Barry Lee

    2003-06-01

    It has been reported in the literature that after lasing dentin the dentin surface has a glassy or globular appearance. Many authors believe this to be recrystallized hydroxyapatite. The purpose of this elemental analysis was to see if any of the silica fiber optic was melted and deposited as these globular structures on the canal wall. Two teeth were used. One was hand-instrumented with files and used as the control, the other was lased with a holmium:YAG laser. A 245-micro low OH- fiber was used with a power setting of 0.75 W, 5 Hz, 94.2 J, and 1134 V to lase the root. The roots were microanalyzed for oxygen, phosphorus, silicon, nitrogen, hydrogen, calcium, and carbon. The percentages for all elements tested were the same for both teeth. Therefore, there was no silicon deposited onto the canal wall of the tooth that was lased. It is concluded that the low OH- silica fiber optic was not melted and deposited onto the dentinal canal wall.

  20. Effects of Mn on the ion absorption and activity of antioxidant enzymes system in the roots of grape%锰对葡萄根中离子吸收及抗氧化酶系统的影响

    Institute of Scientific and Technical Information of China (English)

    尹文彦; 姚银安

    2012-01-01

    以2个葡萄品种(金手指、康拜尔)为材料,采用温室沙培实验,研究不同浓度Mn处理对葡萄根中离子吸收及抗氧化酶活性的影响.结果表明,随着Mn2+浓度的增大,葡萄根中元素含量呈现不同的变化,总体上看Ca和Mg的含量降低,Mn、Cu和Zn的含量增加,Fe含量则随锰处理浓度增加呈先下降后略有升高的趋势.在抗氧化系统中POD活性随 Mn浓度的升高而逐渐降低,而CAT和APX酶活性呈先升高后降低的趋势,SOD活性变化不大,说明保护酶系统形成了一定的适应高锰胁迫的机制,这些抗氧化酶活性的增强能够提高葡萄适应和抵抗重金属胁迫的能力.%Taking two grape varieties (Gold Finger and Campbell) as material, a sand culture experiment in greenhouse was carried out to study effects of various Mn stress on ion absorption and antioxidant enzyme system of grape roots. The results showed that with the increase concentrations of Mn + , the element content in grape roots showed different changes, in general, the contents of Ca and Mg were low levels, contents of Mn, Cu and Zn increased, while the Fe content declined first and then rose slightly with the rising of manganese concentration. The activity of POD with the rising of Mn concentration was decreasing, while the CAT and APX enzyme activities rose first and then declined. SOD maintained stability.

  1. 重茬胁迫下苹果不同砧木幼苗生长及根系吸收的差异%Differences of growth and root absorption of different apple rootstock seedlings in replant stress

    Institute of Scientific and Technical Information of China (English)

    郭小静; 韩甜甜; 王荣; 张贞; 盖瑞; 毛志泉; 陈学森; 吴树敬; 沈向

    2015-01-01

    [Objective] Selecting appropriate rootstocks is one of the most effective methods of preventing apple from replant disease. In order to provide theoretic foundation for screening of anti-replant rootstock materials and breeding anti-replant rootstock varieties, differences of growth and root absorption of three apple rootstock seedlings were compared, and absorption of potassium and calcium ions under the replant stress was discussed in this study.[Methods] One-year-old seedlings of Malus hupehensis Rehd, Malus sieversii( Ledeb. ) Roem and Malus prunifolia ( Willd. ) Borkh were used as the materials, and 0-40 cm rhizosphere soil of 20 years’ orchard which‘Fuji’ apple on M . robusta stock located in Tai’an city was used as matrix. The seedlings were divided into two parts, some of the seedlings were supplied to determine the flow velocity of rhizosphere K+ and Ca2+ under the replant stress by Non-invasive Micro-test Technique on April 25 , 2012 , other seedlings were transplanted into pots of 25 cm wide and 30 cm deep. The height, stem diameter, chlorophyll content and photosynthetic rate of the seedlings were investigated from July to September. The root structure was scanned and dry weight and fresh weight of roots, branches and leaves were measured respectively after the growing season. [Results]The aboveground growth of the three rootstocks is suppressed in different levels under the replant stress. The heights of M. hupehensis have no significant differences before and after the replant stress, while the heights of the other two rootstocks are significantly decreased. The photosynthetic rates have no significant decreases except M. Sieversii. The chlorophyll contents of three rootstocks are significantly decreased and there are no obviously changes in stem diameter. The dry matter of M. sieversii seedlings is significantly decreased under the replant stress, while the root-shoot ratio is increased. Root biomass amounts of the three rootstocks are

  2. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest.

    Science.gov (United States)

    Eissenstat, David M; Kucharski, Joshua M; Zadworny, Marcin; Adams, Thomas S; Koide, Roger T

    2015-10-01

    The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich patches differently from species with relatively fine absorptive roots? We measured traits related to nutrient foraging (root morphology and architecture, root proliferation, and mycorrhizal colonization) across six coexisting arbuscular mycorrhizal (AM) temperate tree species with and without nutrient addition. Root traits such as root diameter and specific root length were highly correlated with root branching intensity, with thin-root species having higher branching intensity than thick-root species. In both fertilized and unfertilized soil, species with thin absorptive roots and high branching intensity showed much greater root length and mass proliferation but lower mycorrhizal colonization than species with thick absorptive roots. Across all species, fertilization led to increased root proliferation and reduced mycorrhizal colonization. These results suggest that thin-root species forage more by root proliferation, whereas thick-root species forage more by mycorrhizal fungi. In mineral nutrient-rich patches, AM trees seem to forage more by proliferating roots than by mycorrhizal fungi.

  3. 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...... processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has...

  4. 外源钙对镉胁迫下南美蟛蜞菊毛状根生长、抗氧化酶活性和镉吸收的缓解效应%Alleviated affect of exogenous CaCl2 on the growth, antioxidative enzyme activities and cadmium absorption efficiency of Wedelia trilobata hairy roots under cadmium stress

    Institute of Scientific and Technical Information of China (English)

    施和平; 王云灵; 曾宝强; 陈利华

    2012-01-01

    In order to study the physiological mechanism of exogenous calcium on the toxicity of heavy metal cadmium (Cd) to Wedelia trilobata hairy roots, the effects of Cd alone, and in combination with different concentrations of Ca on growth, contents of soluble protein and malondialdehyde (MDA), activities of superoxide dismutase (SOD) and peroxidase (POD), Cd2+ absorption in W. trilobata hairy roots were investigated. Cd concentrations lower than 50 umol/L enhanced the growth of hairy roots, while concentrations higher than 100 μmol/L inhibited growth, making the branched roots short and small, and also turning the root tips brown, even black. In comparison with the control (0 μmol/L Cd), the soluble protein content in hairy roots was found to increase when cultured with 10-50 umol/L Cd, and decrease when exposed to a cadmium concentration higher than 100μmol/L Cd. In addition, the activities of POD and SOD activity and MDA content were significantly higher than the control. Compared to the control (hairy roots cultured without 10-30 mmol/L Ca), 100 μmol/L Cd or 300 μmol/L Cd in combination with 10-30 mmol/L Ca resulted in increased growth, causing the main root and secondary roots thicker and also an increase in soluble protein content. On the contrary, MDA content and POD and SOD activities decreased. Quantitative analysis by Atomic Absorption Spectrophotometry showed that W. trilobata hairy roots can absorb and adsorb heavy metal Cd in the ionic form of Cd2+. The maximum content of Cd2+ absorbed by the hairy roots was obtained with a concentration 100 μmol/L Cd2+ while that of Cd2+ adsorbed by hairy roots was achieved with a concentration of 300 μmol/L Cd2+. The exogenous addition of 10-30 mmol/L Ca2+ was found to reduce the absorption, adsorption of Cd2+ and the toxicity of Cd significantly. This reduction in toxicity was caused by the reduction in the absorption of Cd and decreasing the lipid peroxidation through regulating the activities of antioxidant

  5. Absorção e infiltração de água por raízes de batata-doce, através de ferimentos durante a lavagem Water absorption and infiltration in sweet-potato wound roots during washing

    Directory of Open Access Journals (Sweden)

    Adonai Gimenez Calbo

    2000-09-01

    changes of root volume. Partially submerged intact roots and segments were less subject to intercellular water infiltration than the completely submerged ones. The mass increase of submerged intact roots was caused mainly by water absorption, a process which is known to exclude molecules with a size larger than a few nanometers. In transversely segmented roots most water entered by intercellular volume infiltration, which may introduce fungi spores and bacteria and other particles inside the damaged organ.

  6. 水分、养分和寄主对檀香幼苗根系生长及营养吸收的影响%Effects of water, nutrient and host on root growth and nutrient absorption of Santalum album seedling

    Institute of Scientific and Technical Information of China (English)

    李双喜; 杨曾奖; 徐大平; 张宁南; 刘小金

    2015-01-01

    Effects of water ( relative water content 30%, 50% and 70% in substrate ) , nutrient (fertilizer amount per plant 0. 00, 150. 00 and 300. 00 mg) and host (Kuhnia rosmarnifolia Vent.) on root growth indexes (including total length, surface area, dry weight and average diameter of root), root/shoot ratio and nutrient absorption indexes ( including contents of total N, total P and total K in whole plant) of Santalum album Linn. seedling were researched by pot experiment. The results show that with enhancing of relative water content in substrate and fertilizer amount per plant, in general, total length, surface area and dry weight of root of S. album seedling increase, average diameter of root decreases, and contents of total N, total P and total K in whole plant increase. Compared with treatment group without host, planting host can obviously promote increasing of total length, surface area and dry weight of root, and contents of total N, total P and total K in whole plant of S. album seedling. Before root haustorium formation (the 30th day of treatment) and after root haustorium formation (the 80th day of treatment) , average diameter of root of S. album seedling planted together with host decreases, while average diameter of root increases at the 130th day of treatment. At the 130th day of treatment, under conditions of relative water content 70% in substrate and fertilizer amount per plant 300. 00 mg, root/shoot ratio of S. album seedling planted together with host is the lowest only with a value of 0. 19. The result of variance analysis shows that water, nutrient and host can significantly affect total length, surface area, dry weight and average diameter of root, root/shoot ratio and contents of total N, total P and total K in whole plant of S. album seedling. It is suggested that keeping higher relative water content in substrate, higher fertilizer amount per plant and planted together with host can promote root growth, nutrient absorption and above-ground part

  7. 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).

  8. Mycorrhiza alters the profile of root hairs in trifoliate orange.

    Science.gov (United States)

    Wu, Qiang-Sheng; Liu, Chun-Yan; Zhang, De-Jian; Zou, Ying-Ning; He, Xin-Hua; Wu, Qing-Hua

    2016-04-01

    Root hairs and arbuscular mycorrhiza (AM) coexist in root systems for nutrient and water absorption, but the relation between AM and root hairs is poorly known. A pot study was performed to evaluate the effects of four different AM fungi (AMF), namely, Claroideoglomus etunicatum, Diversispora versiformis, Funneliformis mosseae, and Rhizophagus intraradices on root hair development in trifoliate orange (Poncirus trifoliata) seedlings grown in sand. Mycorrhizal seedlings showed significantly higher root hair density than non-mycorrhizal seedlings, irrespective of AMF species. AMF inoculation generally significantly decreased root hair length in the first- and second-order lateral roots but increased it in the third- and fourth-order lateral roots. AMF colonization induced diverse responses in root hair diameter of different order lateral roots. Considerably greater concentrations of phosphorus (P), nitric oxide (NO), glucose, sucrose, indole-3-acetic acid (IAA), and methyl jasmonate (MeJA) were found in roots of AM seedlings than in non-AM seedlings. Levels of P, NO, carbohydrates, IAA, and MeJA in roots were correlated with AM formation and root hair development. These results suggest that AMF could alter the profile of root hairs in trifoliate orange through modulation of physiological activities. F. mosseae, which had the greatest positive effects, could represent an efficient AM fungus for increasing fruit yields or decreasing fertilizer inputs in citrus production.

  9. Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L

    Science.gov (United States)

    Fondren, W. M.; Moore, R.

    1987-01-01

    We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays. Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots. Curvature was always toward the side of the root unto which the agar block was placed. Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots. Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots. These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).

  10. Identiifcation and validation of root-speciifc promoters in rice

    Institute of Scientific and Technical Information of China (English)

    HUANG Li-yu; ZHANG Fan; QIN Qiao; WANG Wen-sheng; ZHANG Ting; FU Bin-ying

    2015-01-01

    Novel promoters that confer root-speciifc expression would be useful for engineering resistance against problems of nutrient and water absorption by roots. In this study, the reverse transcriptase polymerase chain reaction was used to identify seven genes with root-speciifc expression in rice. The isolation and characterization of upstream promoter regions of ifve selected genes rice root-speciifc promoter (rRSP) 1 to 5 (rRSP1-rRSP5) and A2P (the promoter ofOsAct2) revealed that rRSP1, rRSP3, and rRSP5 are particularly important with respect to root-speciifc activities. Furthermore, rRSP1, rRSP3, and rRSP5 were observed to make different contributions to root activities in various species. These three promoters could be used for root-speciifc enhancement of target gene(s).

  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. 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

  13. 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

  14. Rooting gene trees without outgroups: EP rooting.

    Science.gov (United States)

    Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

    2012-01-01

    Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260).

  15. Mercury content of sprouts and harvested roots from treated sweet potato mother roots. [Ipomoea batatas

    Energy Technology Data Exchange (ETDEWEB)

    Huisingh, D.; Nielsen, L.W.

    1972-01-01

    Mercury containing fungicides have been used extensively for seed and root disease control, but data on the fate of the mercury (Hg) are scarce. Experiments were designed to see if Hg applied to propagative sweet potato roots increased the Hg-content of edible roots. Roots were treated with Semesan Bel(hydroxymercurinitrophenol + hydroxymercurichlorophenol), Mertect (Thiabendazole: 2-(4-Thiazolyl)-benzimidazole), or Botran (2,6-Dichloro-4-nitroanaline) at recommended rates or with water. Treated roots were bedded into sandy loam soil, and the plants were harvested at 2 and 3 months after bedding. Some sprouts transplanted at 2 months were grown to maturity, and the harvested roots were analyzed. Hg analyses were performed by flameless atomic absorption. Roots treated prior to planting with Semesan Bel, Mertect, Botran, and water contained 23.0, 0.05, 0.03 and 0.03 ..mu..g/g dry wt, respectively. At the 2-month harvest, the leaves and stems of the Semesan Bel-treated plants contained 5 times more Hg than those of the other treatments. By the 3-month harvest, the amount of Hg in plant leaves and stems from Hg-treated roots was 2 to 3 times that of the others. Fall harvested fleshy roots contained 0.03, 0.02, 0.03, and 0.03 ..mu..g/g dry wt Hg for the Semesan Bel, Mertect, Botran, and water treatments, respectively. This demonstrates that the Hg applied to the mother root was translocated to the new plant, but little if any was translocated to the new fleshy roots.

  16. Absorption and translocation of nitrogen in rhizomes of Leymus chinensis.

    Science.gov (United States)

    Liu, Hongsheng; Liu, Huajie; Song, Youhong

    2011-03-15

    Leymus chinensis is a dominant species in the Inner Mongolia steppe, northern China. Plant growth in northern China grassland is often limited by low soil nitrogen availability. The objective of this study is to investigate whether rhizomes of Leymus chinensis are involved in the contribution of N uptake. The N concentration, (15)N concentration and (15)N proportion in roots, rhizomes and shoots after 48 h exposure of roots (L(root)) and rhizomes (L(rhizo)) separately and roots and rhizomes together (L(r+r)) to 0.1 mM (15)NH (4)(15)NO(3) solution were measured using root-splitting equipment and stable isotope ((15)N) techniques, respectively. The N content and dry mass were not affected by the labeling treatment. In contrast, the (15)N concentration in shoots, rhizomes and roots was significantly increased by the labeling in rhizomes, indicating that the inorganic nitrogen was absorbed via rhizomes from the solution and can be transported to other tissues, with preference to shoots rather than roots. Meanwhile, the absolute N absorption and translocation among compartments were also calculated. The N absorption via rhizomes was much smaller than via roots; however, the uptake efficiency per surface unit via rhizomes was greater than via roots. The capacity and high efficiency to absorb N nutrient via rhizomes enable plants to use transient nutrient supplies in the top soil surface.

  17. Porosity and liquid absorption of cement paste

    DEFF Research Database (Denmark)

    Krus, M.; Hansen, Kurt Kielsgaard; Kunzel, H. M.

    1997-01-01

    be a slowing-down effect which is related to water because the absorption of organic liquids, such as hexane, is quite normal. Measurements of the porosity of hardened cement paste determined by helium pycnometry and water saturation show that water molecules can enter spaces in the microstructure which...... are not accessible to the smaller helium atoms. Considering the results of dilatation tests both before and after water and hexane saturation, it seems possible that a contraction of capillary pores due to moisture-related swelling of the cement gel leads to the non-linear water absorption over the square root...

  18. Contrasting the morphology, anatomy and fungal colonization of new pioneer and fibrous roots.

    Science.gov (United States)

    Zadworny, Marcin; Eissenstat, David M

    2011-04-01

    Not all roots born as first-order branches are the same and this has important consequences for overall function. We hypothesized that, compared with fibrous roots, pioneer roots are built to live longer at the expense of absorptive capacity. We tested this hypothesis by investigating pioneer and fibrous roots in their first 14 d of life in the arbuscular mycorrhizal tree species: Acer negundo, Acer saccharum, Juglans nigra, Liriodendron tulipifera and Populus tremuloides. Root observations were made with root-access boxes that allowed roots to be sampled at known ages in field-grown trees. Compared to fibrous roots, pioneer roots had larger diameter, lower specific root length, greater average length and a lack of mycorrhizal or nonmycorrhizal fungal colonization. Pioneer roots < 14 d old had more layers of hypodermis with a lower percentage of putative passage cells and more protoxylem groups than similar age fibrous roots. Our results suggest that pioneer roots are constructed for defense against biotic and abiotic challenges, exploration of soil distal to the stem, high fibrous root branching and secondary development with high axial hydraulic conductivity at the expense of mycorrhizal colonization and high absorptive capacity for water and nutrients.

  19. Optimization of Detecting Conditions of Cd Element in Root of A maranthus hypochondriacus using Flame Atomic Absorption Based on Response Surface Methodology%火焰原子吸收法检测籽粒苋根中镉含量影响因素的响应面优化

    Institute of Scientific and Technical Information of China (English)

    晋海军; 徐铭键; 陈惠; 张世熔; 布同良; 唐自钟; 孙蓉; 刘默洋

    2015-01-01

    To optimize the detecting conditions of Cd element in root of A maranthus hypochondriacus using flame atomic absorption based on response surface methodology. On the basis of single factor experiment, effects of lamp current, slit width, acetylene/air flow ratio and burner height were investigated based on the Box-Behnken design of Design Expert V 8.0.5b on the absorbance value of Cd element in root of Amaranthus hypochondriacus. The optimal detecting conditions were as follows:lamp current 5.67 mA, slit width 0.62 nm, acetylene/air flow ratio 0.17;burner height 5.14 mm, and the theoretical prediction of the absorbance was 0.209 4. The experimental results showed that the theoretical value of absorbance was close to that of the real detection, and the relative standard deviation was 0.94%, and the recovery rates ranged from 96.3%to 103.7%. This showed that the method had a good reproducibility, and the data was accurate and reliable. This experiment will provide technical data for accurate detection of cadmium content of different parts (roots, stems, leaves and fruits) and screening of new varieties of cadmium resistance in A maranthus hypochondriacus.%采用响应面法优化籽粒苋(Amaranthus hypochondriacus)根中镉元素的火焰原子吸收检测条件。在单因素试验的基础上,本研究利用Design Expert V 8.0.5b软件中的Box-Benhnken试验设计,研究灯电流、狭缝宽度、乙炔/空气流量比和燃烧器高度4个因素对籽粒苋根系中镉吸光度值的影响。用响应面分析法得出最优的测定条件为:灯电流5.67 mA;狭缝宽度0.62 nm;乙炔/空气流量比0.17(1/6);燃烧器高度5.14 mm,此时的理论预测吸光度值为0.2094。通过验证实验证实:吸光度的理论预测值与真实测定值接近,样品检测中的相对标准偏差0.94%,加标回收率在96.3%~103.7%之间,说明该检测方法重现性好,数据准确可靠。本实验将为下一步准确检测籽粒苋不同部

  20. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  1. Conjoined lumbosacral nerve roots

    Directory of Open Access Journals (Sweden)

    Atila Yılmaz

    2012-03-01

    Full Text Available Lumbosacral nerve root anomalies are a rare group ofcongenital anatomical anomalies. Various types of anomaliesof the lumbosacral nerve roots have been documentedin the available international literature. Ttheseanomalies may consist of a bifid, conjoined structure, ofa transverse course or of a characteristic anastomizedappearance. Firstly described as an incidental findingduring autopsies or surgical procedures performed forlumbar disk herniations and often asymptomatic, lumbosacralnerve root anomalies have been more frequentlydescribed in the last years due to the advances made inradiological diagnosis.

  2. Sap flow measurements of lateral tree roots in agroforestry systems.

    Science.gov (United States)

    Lott, J. E.; Khan, A. A. H.; Ong, C. K.; Black, C. R.

    1996-01-01

    Successful extension of agroforestry to areas of the semi-arid tropics where deep reserves of water exist requires that the tree species be complementary to the associated crops in their use of water within the crop rooting zone. However, it is difficult to identify trees suitable for dryland agroforestry because most existing techniques for determining water uptake by roots cannot distinguish between absorption by tree and crop roots. We describe a method for measuring sap flow through lateral roots using constant temperature heat balance gauges, and the application of this method in a study of complementarity of water use in agroforestry systems containing Grevillea robusta A. Cunn. Sap flow gauges were attached to the trunks and roots of Grevillea with minimum disturbance to the soil. Thermal energy emanating from the soil adversely affected the accuracy of sap flow gauges attached to the roots, with the result that the uncorrected values were up to eightfold greater than the true water uptake determined gravimetrically. This overestimation was eliminated by using a calibration method in which nonconducting excised root segments, with sap flow gauges attached, were placed adjacent to the live roots. The power consumption and temperature differentials of the excised roots were used to correct for external sources and internal losses of heat within the paired live root. The fraction of the total sap flow through individual trees supplied by the lateral roots varied greatly between trees of similar canopy size. Excision of all lateral roots, except for one to which a heat balance gauge was attached, did not significantly increase sap flow through the intact root, suggesting that it was functioning at near maximum capacity.

  3. Experimental study on the response of extracellular electric potential difference of plant during the water absorption of root%植物细胞外电势差信号对根系吸水过程的响应特征

    Institute of Scientific and Technical Information of China (English)

    杨磊; 周启友; 吴世艳

    2011-01-01

    植物细胞外电势差信号能够反映植物生理信息,通过插入黄杨树干和土壤金属电极,然后测定这种细胞外电势差,并借助小波变换方法,探究其对根系吸水过程的响应.结果表明:加水后必然产生动作电位信号,在土壤含水量相似的条件下,加水量越大,动作电位信号越强,而在加水量相当的条件下,土壤含水量越低,动作电位信号越强;树干-土壤之间的电势差在加水后波动幅度增加,并呈衰减趋势,当波动幅度衰减到几毫伏量级时,树干-土壤之间的电势差出现日变化规律,即在正午左右电势差出现极值.%Previous studies have shown that extracellular electric potential difference signals could reveal the physiological information of plant.When the plant is stimulated by the change of environment,such as water absorption and temperature variation,electrical signals that could be obtained by the instruments will generate and transport by cells.In this study,metal electrodes are inserted into a boxtree trunk and the soil around the tree to capture the action potential(AP).Water irrigation is chosen as a stimulation method and irrigation events are repeated in different soil conditions.Since the measured electrical signal is slightly disturbed by noise and the plant electrical signal has a property of low frequency,wavelet transform method is applied to seek the information of AP transmission.During the AP signal is transporting,electric potential difference is measured in high frequency at the same time to catch the AP,with the aim to explore the electrical response of water absorption of root.The results indicate that: Irrigation events with different volume of water give rise to action potential under various conditions of soil condition.When the volume of irrigation water is similar,the larger volume creates the stronger action signal.Meanwhile,while the water amount is close,the lower soil moisture content brings the stronger

  4. 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...

  5. 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.

  6. Root lattices and quasicrystals

    Science.gov (United States)

    Baake, M.; Joseph, D.; Kramer, P.; Schlottmann, M.

    1990-10-01

    It is shown that root lattices and their reciprocals might serve as the right pool for the construction of quasicrystalline structure models. All noncrystallographic symmetries observed so far are covered in minimal embedding with maximal symmetry.

  7. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes.

    Science.gov (United States)

    McCormack, M Luke; Dickie, Ian A; Eissenstat, David M; Fahey, Timothy J; Fernandez, Christopher W; Guo, Dali; Helmisaari, Heljä-Sisko; Hobbie, Erik A; Iversen, Colleen M; Jackson, Robert B; Leppälammi-Kujansuu, Jaana; Norby, Richard J; Phillips, Richard P; Pregitzer, Kurt S; Pritchard, Seth G; Rewald, Boris; Zadworny, Marcin

    2015-08-01

    Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally - a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere.

  8. Nutrition and magnesium absorption.

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium abs

  9. Bioacoustic Absorption Spectroscopy

    Science.gov (United States)

    2016-06-07

    frequencies (Ching and Weston, 1971). RESULTS Measured resonance frequencies of absorption lines, which were attributed to adult (~ 1.3 khz) and juvenile ...of adult and juvenile sardines. These results suggest that bioacoustic absorption spectroscopy measurements permit isolation of juvenile from adult...from broadband tomographic transmission loss measurements over large areas . 2. Depths of sardines and contours of phytoplankton concentrations vs. time

  10. The HI absorption "Zoo"

    NARCIS (Netherlands)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-01-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis o

  11. Modeling root reinforcement using root-failure Weibull survival function

    Directory of Open Access Journals (Sweden)

    M. Schwarz

    2013-03-01

    Full Text Available Root networks contribute to slope stability through complicated interactions that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamic of root turnover, the quantification of root reinforcement on steep slope is challenging and consequently the calculation of slope stability as well. Although the considerable advances in root reinforcement modeling, some important aspect remain neglected. In this study we address in particular to the role of root strength variability on the mechanical behaviors of a root bundle. Many factors may contribute to the variability of root mechanical properties even considering a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw. The results show that, for both laboratory and field datasets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the tensile force and the elasticity of the roots are the most important equations, as well as the root distribution. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root

  12. Biocompatibility of Er:YSGG laser radiated root surfaces

    Science.gov (United States)

    Benthin, Hartmut; Ertl, Thomas P.; Schmidt, Dirk; Purucker, Peter; Bernimoulin, J.-P.; Mueller, Gerhard J.

    1996-01-01

    Pulsed Er:YAG and Er:YSGG lasers are well known to be effective instruments for the ablation of dental hard tissues. Developments in the last years made it possible to transmit the laser radiation at these wavelengths with flexible fibers. Therefore the application in the periodontal pocket may be possible. The aim of this study was to evaluate the in-vitro conditions to generate a bioacceptable root surface. Twenty extracted human teeth, stored in an antibiotic solution, were conventionally scaled, root planed and axially separated into two halves. Two main groups were determined. With the first group laser radiation was carried out without and in the second group with spray cooling. The laser beam was scanned about root surface areas. Laser parameters were varied in a selected range. The biocompatibility was measured with the attachment of human gingival fibroblasts and directly compared to conventionally treated areas of the root surfaces. The fibroblasts were qualified and counted in SEM investigations. On conventionally treated areas gingival fibroblasts show the typical uniform cover. In dependance on the root roughness after laser treatment the fibroblasts loose the typical parallel alignment to the root surface. With spray cooling a better in-vitro attachment could be obtained. Without spray cooling the higher increase in temperature conducted to less bioacceptance by the human gingival fibroblasts to the root surface. These results show the possibility of producing bioacceptable root surfaces with pulsed laser radiation in the range of very high water absorption near 3 micrometer.

  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. Produção de matéria seca, crescimento radicular e absorção de cálcio, fósforo e alumínio por coffea canephora e coffea arabica sob influência da atividade do alumínio em solução Dry matter production, root growth and calcium, phosphorus and aluminum absorption by coffea canephora and coffea arabica under influence of aluminum activity in solution

    Directory of Open Access Journals (Sweden)

    Edson Marcio Mattiello

    2008-02-01

    Full Text Available Este trabalho teve como objetivo avaliar a produção de matéria seca, o crescimento radicular e a absorção e distribuição do Ca, P e Al nas folhas, no caule e nas raízes de dois clones de café conilon (Coffea canephora (Mtl 25 e Mtl 27 e de uma variedade de café Catuaí Amarelo (Coffea arabica, cultivados em solução nutritiva com atividade crescente de Al3+. As plantas foram cultivadas em vasos com capacidade para 5 L, contendo solução nutritiva de Hoagland & Arnon, modificada. Após oito dias de adaptação, as plantas foram submetidas a concentrações de Al de 0, 500, 1.000 e 2.000 µmol L-1, que corresponderam a atividades de Al3+ em solução, estimadas pelo software GEOCHEM, de 20,68, 50,59, 132,9 e 330,4 µmol L-1, respectivamente. Foram determinados os teores de Ca, Al e P na planta. O sistema radicular foi separado, para determinação da área e do comprimento. A variedade Catuaí Amarelo (Coffea arabica apresentou-se menos sensível ao Al3+, quando comparada aos clones de conilon (Coffea canephora. O clone de conilon Mtl 25 foi menos sensível ao Al3+ em relação ao Mtl 27. O aumento da atividade de Al3+ promoveu redução nos teores de P e Ca nas folhas e raízes do cafeeiro, especialmente nos clones Mtl 25 e Mtl 27. O acúmulo de Al no sistema radicular e a restrição do transporte para a parte aérea são importantes fatores na tolerância de plantas ao Al3+.This study had the objective of evaluating the dry matter production, root growth, and the absorption and distribution of Ca, P and Al in the leaves, stem and roots of two Conilon (Coffea canephora coffee clones (Mtl 25 and Mtl 27 and the coffee variety Catuaí Amarelo (Coffea arabica grown in nutrient solution with increasing Al3+ activity. The plants were cultivated in 5 L pots, containing modified Hoagland & Arnold nutrient solution. After eight days of adaptation, the plants were subjected to Al concentrations of 0, 500, 1.000 and 2.000 mol L-1, which

  15. Discussion on Photoreceptor for Negative Phototropism in Rice Roots

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-xia; WANG Zhong; SUO Biao; GU Yun-jie; WANG Hui-hui; CHEN Yong-hui; DAI Yun-xia

    2007-01-01

    To properly explore the photoreceptor for the negative phototropism in rice (Oryza sativa L.) root, lights with different wavelengths were applied to investigate the effect of light quality on phototropic bending. The phototropic bending could be induced prominently by blue/ultraviolet light, whereas not by red or far-red light. The absorption spectrum of the extracted solution from rice root cap had two peaks at 350 nm and 450 nm, respectively, and the molecular weight of the 120 kD protein in the root cap under unilateral light was larger than that under the dark. It suggested that the blue light receptor might be the photoreceptor for the negative phototropism in rice root.

  16. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  17. The Roots Of Alienation

    Science.gov (United States)

    Bronfenbrenner, Urie

    1973-01-01

    Alienation in our society takes several forms--withdrawal, hostility, or efforts to reform. The author traces the roots of alienation to our neglect of many of the needs of children, particularly their need for interaction with adults. Among his many recommendations are: modified work schedules to permit more time with children and systems for…

  18. 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.

  19. Bioremediation of phenolic compounds from water with plant root surface peroxidases

    Energy Technology Data Exchange (ETDEWEB)

    Adler, P.R.; Arora, R.; El Ghaouth, A. [West Virginia Univ., Morgantown, WV (United States)] [and others

    1994-09-01

    Peroxidases have been shown to polymerize phenolic compounds, thereby removing them from solution by precipitation. Others have studied the role of root surface associated peroxidases as a defense against fungal root pathogens; however, their use in detoxification of organic pollutants in vivo at the root surface has not been studied. Two plant species, waterhyacinth [Eichhornia crassipes (C. Mart) Solms-Laub.] and tomato (Lycopersicon esculentum L.), were tested for both in vitro and in vivo peroxidase activity on the root surface. In vitro studies indicated that root surface peroxidase activities were 181 and 78 nmol tetraguaiacol formed min{sup -1} g{sup -1} root fresh wt., for tomato and waterhyacinth, respectively. Light microscope studies revealed that guaiacol was polymerized in vivo at the root surface. Although peroxidase was evenly distributed on tomato roots, it was distributed patchily on waterhyacinth roots. In vitro studies using gas chromatography-mass spectrometry (GC-MS) showed that the efficiency of peroxidase to polymerize phenols vary with phenolic compound. We suggest that plants may be utilized as a source of peroxidases for removal of phenolic compounds that are on the EPA priority pollutant list and that root surface peroxidases may minimize the absorption of phenolic compounds into plants by precipitating them at the root surface. In this study we have identified a new use for root-associated proteins in ecologically engineering plant systems for bioremediation of phenolic compounds in the soil and water environment. 25 refs., 2 figs., 2 tabs.

  20. Root Uptake of Lipophilic Zinc−Rhamnolipid Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, Samuel P.; McLaughlin, Michael J.; Cakmak, Ismail; Hettiarachchi, Ganga M.; Scheckel, Kirk G.; Karkkainen, Michael (Sabanci); (EPA); (CSIRO/LW); (Adelaide)

    2009-06-16

    This study investigated the formation and plant uptake of lipophilic metal-rhamnolipid complexes. Monorhamnosyl and dirhamnosyl rhamnolipids formed lipophilic complexes with copper (Cu), manganese (Mn), and zinc (Zn). Rhamnolipids significantly increased Zn absorption by Brassica napus var. Pinnacle roots in {sup 65}Zn-spiked ice-cold solutions, compared with ZnSO{sub 4} alone. Therefore, rhamnolipid appeared to facilitate Zn absorption via a nonmetabolically mediated pathway. Synchrotron XRF and XAS showed that Zn was present in roots as Zn-phytate-like compounds when roots were treated with Zn-free solutions, ZnSO{sub 4}, or Zn-EDTA. With rhamnolipid application, Zn was predominantly found in roots as the Zn-rhamnolipid complex. When applied to a calcareous soil, rhamnolipids increased dry matter production and Zn concentrations in durum (Triticum durum L. cv. Balcali-2000) and bread wheat (Triticum aestivum L. cv. BDME-10) shoots. Rhamnolipids either increased total plant uptake of Zn from the soil or increased Zn translocation by reducing the prevalence of insoluble Zn-phytate-like compounds in roots.

  1. 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...

  2. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  3. 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.

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

    Science.gov (United States)

    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 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

  5. Metagenomics at Grass Roots

    Indian Academy of Sciences (India)

    Sudeshna Mazumdar-Leighton; Vivek K Choudhary

    2017-03-01

    Metagenomics is a robust, interdisciplinary approach for studyingmicrobial community composition, function, and dynamics.It typically involves a core of molecular biology, microbiology,ecology, statistics, and computational biology. Excitingoutcomes anticipated from these studies include unravelingof complex interactions that characterize the ecologicalmilieu of microbial communities. Diverse habitats fromwhich metagenomes have been reported include human guts,caterpillar guts, thermal vents in oceans, ore deposits, polarcaps, and even soils that adhere to plant roots. Knowledgegenerated from metagenomic projects has tremendous potentialto benefit human health, agriculture, and ecosystemfunctions. This article provides a brief history of technicaladvances in metagenomics, including DNA sequencing methods,and some case studies. A specific example is providedof microbial metagenomes found at the roots of native grassspecies (family Poaceae) that can grow on degraded lands undergoingrevegetation.

  6. 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.

  7. Rooting an Android Device

    Science.gov (United States)

    2015-09-01

    tools that grant root privileges for both Windows and Linux . For the Linux system, open a shell window and use “cd” command to change the directory...defined as a process of gaining administrative commands and functions of an operating system (OS). In order to monitor live network traffic on any... Linux -based or, in this case, Android system, it is necessary to have administrative rights to gain access to any of the hardware devices, such as the

  8. Integrated numerical model of nitrogen transportation, absorption and transformation by two-dimension in soil-crop system

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-qi; SHU Yan; QI Yong-qiang; ZHANG Jun

    2005-01-01

    A series of simulation experiments of nitrogen transportation, absorption and transformation were conducted, and the different cropping patterns of winter wheat and wastewater irrigation plans were taken into consideration. Based on the experiments, an integrated model of crop growth, roots distribution, water and nitrogen absorption by roots, water and nitrogen movement and transformation in soilcrop system by two-dimension was developed. Parameters and boundary conditions were identified and an effective computing method for optimizing watering and wastewater irrigating plans was provided.

  9. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  10. AtOPR3 specifically inhibits primary root growth in Arabidopsis under phosphate deficiency.

    Science.gov (United States)

    Zheng, Hongyan; Pan, Xiaoying; Deng, Yuxia; Wu, Huamao; Liu, Pei; Li, Xuexian

    2016-01-01

    The primary root plays essential roles in root development, nutrient absorption, and root architectural establishment. Primary root growth is generally suppressed by phosphate (P) deficiency in A. thaliana; however, the underlying molecular mechanisms are largely elusive to date. We found that AtOPR3 specifically inhibited primary root growth under P deficiency via suppressing root tip growth at the transcriptional level, revealing an important novel function of AtOPR3 in regulating primary root response to the nutrient stress. Importantly, AtOPR3 functioned to down-regulate primary root growth under P limitation mostly by its own, rather than depending on the Jasmonic acid signaling pathway. Further, AtOPR3 interacted with ethylene and gibberellin signaling pathways to regulate primary root growth upon P deficiency. In addition, the AtOPR3's function in inhibiting primary root growth upon P limitation was also partially dependent on auxin polar transport. Together, our studies provide new insights into how AtOPR3, together with hormone signaling interactions, modulates primary root growth in coping with the environmental stress in Arabidopsis.

  11. Growth, Nitrogen Uptake and Flow in Maize Plants Affected by Root Growth Restriction

    Institute of Scientific and Technical Information of China (English)

    Liang-zheng Xu; Jun-fang Niu; Chun-jian Li; Fu-suo Zhang

    2009-01-01

    The objective of the present study was to investigate the influence of a reduced maize root-system size on root growth and nitrogen (N) uptake and flow within plants. Restriction of shoot-borne root growth caused a strong decrease in the absorption of root: shoot dry weight ratio and a reduction in shoot growth. On the other hand, compensatory growth and an increased N uptake rate in the remaining roots were observed. Despite the limited long-distance transport pathway in the mesocotyl with restriction of shoot-borne root growth, N cycling within these plants was higher than those in control plants, implying that xylem and phloem flow velocities via the mesocotyl were considerably higher than in plants with an intact root system. The removal of the seminal roots in addition to restricting shoot-borne root development did not affect whole plant growth and N uptake, except for the stronger compensatory growth of the primary roots. Our results suggest that an adequate N supply to maize plant is maintained by compensatory growth of the remaining roots, increased N uptake rate and flow velocities within the xylem and phloem via the mesocotyl, and reduction in the shoot growth rate.

  12. Effects of Aeration on Root Physiology and Nitrogen Metabolism in Rice

    Institute of Scientific and Technical Information of China (English)

    XU Chun-mei; WANG Dan-ying; CHEN Song; CHEN Li-ping; ZHANG Xiu-fu

    2013-01-01

    In order to clarify the effects of aeration on root nitrogen metabolism in rice seedlings,rice cultivars Guodao 6 (indica) and Xiushui 09 (japonica) were investigated for root growth,the activities of glutamine synthetase (GS),glutamic acid-pyruvic acid transaminase (GPT) and glutamic acid oxaloacetate transaminase (GOT),the nitrate (NO3-N) concertration,the contents of free amino acids and soluble sugar in root under hydroponics with continuous aeration treatment.The results showed that rice seedlings grown in oxygenation solutions had higher root dry matter,longer root length,stronger root activity and larger root absorption area compared with the control.In addition,the contents of soluble sugar,root vigor and the activities of GS,GOT and GPT in the aeration solutions were higher than those in the control.The results also indicated that the activities of enzymes involved in root nitrogen metabolism of Xiushui 09 were enhanced by aeration,however,there was no significant influence on root nitrogen metabolism of Guodao 6,which suggested that effect of oxygenation on rice root nitrogen metabolism might be genotype-specific.

  13. Adsorption of Eu(III) onto roots of water hyacinth

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, C.; Mielke, R.E.; Dimaquibo, D.; Curtis, A.J. [Northern Arizona Univ., Flagstaff, AZ (United States). Dept. of Chemistry; Dewitt, J.G. [San Francisco State Univ., San Francisco, CA (United States)

    1999-05-01

    The water hyacinth (Eichhornia crassipes) has drawn attention as a plant capable of removing pollutants, including toxic metals, from water. The authors are interested in the capacity of the water hyacinth to remediate aquatic environments that have been contaminated with the lanthanide metal, europium Eu(III). Using scanning electron microscopy (SEM) they have been able to determine that Eu(III) is adsorbed onto the surface of the roots from water and that the highest concentration of Eu(III) is on the root hairs. X-ray absorption spectroscopy (XAS) techniques were used to speciate the Eu(III) adsorbed onto the surface of the roots. The XAS data for Eu-contaminated water hyacinth roots provides evidence of a Eu-oxygen environment and establishes that Eu(III) is coordinated to 10--11 oxygen atoms at a distance of 2.44 {angstrom}. This likely involves binding of Eu(III) to the root via carboxylate groups and hydration of Eu(III) at the root surface.

  14. A novel role for the root cap in phosphate uptake and homeostasis.

    Science.gov (United States)

    Kanno, Satomi; Arrighi, Jean-François; Chiarenza, Serge; Bayle, Vincent; Berthomé, Richard; Péret, Benjamin; Javot, Hélène; Delannoy, Etienne; Marin, Elena; Nakanishi, Tomoko M; Thibaud, Marie-Christine; Nussaume, Laurent

    2016-04-06

    The root cap has a fundamental role in sensing environmental cues as well as regulating root growth via altered meristem activity. Despite this well-established role in the control of developmental processes in roots, the root cap's function in nutrition remains obscure. Here, we uncover its role in phosphate nutrition by targeted cellular inactivation or phosphate transport complementation in Arabidopsis, using a transactivation strategy with an innovative high-resolution real-time (33)P imaging technique. Remarkably, the diminutive size of the root cap cells at the root-to-soil exchange surface accounts for a significant amount of the total seedling phosphate uptake (approximately 20%). This level of Pi absorption is sufficient for shoot biomass production (up to a 180% gain in soil), as well as repression of Pi starvation-induced genes. These results extend our understanding of this important tissue from its previously described roles in environmental perception to novel functions in mineral nutrition and homeostasis control.

  15. Back to the roots!

    DEFF Research Database (Denmark)

    Woermann, Niklas

    2017-01-01

    This article argues that one can revive the critical edge that postmodernist theory has brought to marketing, thinking without subscribing to any particular school of (critical) theory by following the principle of methodological situationalism. The roots of postmodernist critique lie in careful...... of social order into account, hence fail to provide sensible insight. I propose the principle of methodological situationalism as a litmus test to the analytical strength of a theory or piece of research. The principle states that theoretically adequate accounts of social phenomena must be grounded...

  16. The Roots of Beowulf

    Science.gov (United States)

    Fischer, James R.

    2014-01-01

    The first Beowulf Linux commodity cluster was constructed at NASA's Goddard Space Flight Center in 1994 and its origins are a part of the folklore of high-end computing. In fact, the conditions within Goddard that brought the idea into being were shaped by rich historical roots, strategic pressures brought on by the ramp up of the Federal High-Performance Computing and Communications Program, growth of the open software movement, microprocessor performance trends, and the vision of key technologists. This multifaceted story is told here for the first time from the point of view of NASA project management.

  17. Acoustic absorption by sunspots

    Science.gov (United States)

    Braun, D. C.; Labonte, B. J.; Duvall, T. L., Jr.

    1987-01-01

    The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system centered on the sunspot. From measurements of the differences in power between waves traveling outward and inward, it is demonstrated that sunspots appear to absorb as much as 50 percent of the incoming acoustic waves. It is found that for all three sunspots observed, the amount of absorption increases linearly with horizontal wavenumber. The effect is present in p-mode oscillations with wavelengths both significantly larger and smaller than the diameter of the sunspot umbrae. Actual absorption of acoustic energy of the magnitude observed may produce measurable decreases in the power and lifetimes of high-degree p-mode oscillations during periods of high solar activity.

  18. Chaotic systems with absorption

    CERN Document Server

    Altmann, Eduardo G; Tél, Tamás

    2013-01-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate $\\kappa$ in terms of the natural conditionally-invariant measure of the system; (ii) an increased multifractality when compared to the spectrum of dimensions $D_q$ obtained without taking absorption and return times into account; and (iii) a generalization of the Kantz-Grassberger formula that expresses $D_1$ in terms of $\\kappa$, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  19. Hydrogen Absorption by Niobium.

    Science.gov (United States)

    1982-04-13

    incorporate an independent means for ascertaining surface cleanliness (e.g. AES). The form of the absorption curve in Fig. 7 appears to agree with that...very interesting study and is well within the capabilities of the systen designed, if the surface cleanliness can be assured. Wire specimens have a...assessing surface cleanliness would be an important supporting technique for understanding the results of these measurements. The simple kinetic

  20. Photoinduced absorption of polyalkylthienylenevinylenes

    Energy Technology Data Exchange (ETDEWEB)

    Botta, C. (Ist. di Chimica delle Macromolecole (CNR), Milano (Italy)); Bradley, D.D.C. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Friend, R.H. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Musco, A. (Ist. di Scienze Chimiche, Univ. di Urbino (Italy))

    1993-03-15

    We present a photoinduced absorption study of alkyl substituted poly(2,5-thienylenevinylene)s. Three photoinduced states are detected in both the solid state and in solution. The two low-energy bands are assigned to bipolarons, while a third band peaked near the band edge has a different origin. In solution photoexcitated states are very long-lived and we propose that photoexcitation recombine via a solvent-assisted photo-doping mechanism. (orig.)

  1. CRECIMIENTO, ABSORCIÓN DE FÓSFORO Y MORFOLOGÍA DE LA RAÍZ EN ESPÁRRAGOS INOCULADOS CON HONGOS MICORRIZALES Y PSEUDOMONAS FLUORESCENTES GROWTH, PHOSPHORUS ABSORPTION AND ROOT MORPHOLOGY OF ASPARAGUS INOCCULATED WITH MYCORRHIZAL FUNGI AND FLUORESCENT PSEUDOMONAS

    Directory of Open Access Journals (Sweden)

    Juan Carlos Pérez Naranjo

    2004-12-01

    Full Text Available En un experimento bajo invernadero se evaluaron los efectos de la aplicación de fósforo (P y la inoculación con Glomus fistulosum y Pseudomonas aeruginosa sobre el crecimiento, la longitud de la raíz y la absorción de P por plantas de espárrago sembradas en un Alic Melanudand. La inoculación con G. fistulosum incrementó significativamente la masa seca de la parte aérea y de raíces, la longitud de raíces primarias y secundarias y la absorción de P por las plantas. La aplicación de P aumentó significativamente el P disponible en el suelo (Bray II; sin embargo, a pesar de tal incremento no hubo aumento significativo del crecimiento de las plantas. La inoculación con P. aeruginosa no tuvo efecto significativo sobre las variables estudiadas, ni se encontraron interacciones significativas entre los factores.A greenhouse experiment evaluated the effects of phosphorus (P application and inoculation with Glomus fistulosum and Pseudomonas aeruginosa on growth, root length, and P uptake of Asparagus officinalis grown on Alic Melanudand. Inoculation with G. fistulosum significantly increased shoot and root dry weight, primary and secondary root lengths, and plant P uptake. Phosphorus application significantly increased extractable P in the soil (Bray II, but despite this increase, there was no significant increase in plant growth. Inoculation with P. aeruginosa had no significant effect on the variables studied, nor were there significant interactions among the factors.

  2. [Flexible root posts].

    Science.gov (United States)

    Vadachkoriia, N R; Mandzhavidze, N A; Gumberidze, N Sh

    2009-02-01

    The article discusses the current state of restoration techniques of root canal treatment. Nowadays, technical progress allows manufacturers to develop flexible fiberglass posts, aspiring not only to an excellent aesthetics and mechanical properties (first of all, in comparison with metal and cast posts), but also to maintenance of their radio density and a wide range of forms. Growth of fiberglass posts popularity testifies to their clinical efficiency that also is confirmed by results of long-term researches. Introduction of fiberglass posts in a dental practice has rendered huge influence on restoration techniques of root canal treatment. Convincing factors of fiberglass posts superiority provide restoration the appearance similar with the natural dentition; possess close to dentine elasticity; creation of monolithic structure with hard tooth tissues and composite cement, posts, in case of need, can be easily adjusted on length, adhesive linkage of posts gives them additional stability. Modern researches have confirmed that only elastic, namely carbon fiber and the fiberglass posts made of modern technologies possess similar physical properties, as tooth structure. They can create reliable biomimetic design; solve a complex of aesthetic and functional restoration problems.

  3. Multivariate ultrametric root counting

    CERN Document Server

    Avendano, Martin

    2011-01-01

    Let $K$ be a field, complete with respect to a discrete non-archimedian valuation and let $k$ be the residue field. Consider a system $F$ of $n$ polynomial equations in $K\\vars$. Our first result is a reformulation of the classical Hensel's Lemma in the language of tropical geometry: we show sufficient conditions (semiregularity at $w$) that guarantee that the first digit map $\\delta:(K^\\ast)^n\\to(k^\\ast)^n$ is a one to one correspondence between the solutions of $F$ in $(K^\\ast)^n$ with valuation $w$ and the solutions in $(k^\\ast)^n$ of the initial form system ${\\rm in}_w(F)$. Using this result, we provide an explicit formula for the number of solutions in $(K^\\ast)^n$ of a certain class of systems of polynomial equations (called regular), characterized by having finite tropical prevariety, by having initial forms consisting only of binomials, and by being semiregular at any point in the tropical prevariety. Finally, as a consequence of the root counting formula, we obtain the expected number of roots in $(K...

  4. Corrosion Problems in Absorption Chillers

    Science.gov (United States)

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  5. 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.

  6. 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.

  7. Converting Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2013-01-01

    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a sample and non-uniform intensity in the reverberation chambers under test. In this study, conversion methods from Sabine absorption...... coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations...

  8. Acoustic Absorption Characteristics of People.

    Science.gov (United States)

    Kingsbury, H. F.; Wallace, W. J.

    1968-01-01

    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  9. Spatial distribution characteristics of fine roots of Populus euphratica in a desert riparian forest

    Institute of Scientific and Technical Information of China (English)

    Jianhua SI; Qi FENG; Jianlin LI; Jian ZHAO

    2008-01-01

    The soil-plant system is a very important sub-system of the soil-plant-atmosphere continuum (SPAC). The water uptake by plant roots is an important subject in the research on water transport in this SPAC and is also the most active study direction in the fields of ecology, hydrology and environment. The study of the spatial dis-tribution pattern of fine roots of plants is the basis of constructing a water absorption model of plant roots. Our study on the spatial distribution pattern of fine roots of Populus euphratica in a desert riparian forest shows that the density distribution of its root lengths can be expressed horizontally as a parabola. The fine roots are concen-trated within the range of 0-350 cm from the tree trunk and their amount accounts for 91.9% of the total root mass within the space of 0-500 cm. In the vertical dir-ection, the density distribution of the fine root lengths shows a negative exponential relation with soil depth. The fine roots are concentrated in the 0-80 cm soil layer, accounting for 96.8% of the total root mass in the 0-140 cm soil layer.

  10. Comparing Leaf and Root Insertion

    Directory of Open Access Journals (Sweden)

    Jaco Geldenhuys

    2010-07-01

    Full Text Available We consider two ways of inserting a key into a binary search tree: leaf insertion which is the standard method, and root insertion which involves additional rotations. Although the respective cost of constructing leaf and root insertion binary search trees trees, in terms of comparisons, are the same in the average case, we show that in the worst case the construction of a root insertion binary search tree needs approximately 50% of the number of comparisons required by leaf insertion.

  11. Absorption heat pumps

    Science.gov (United States)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  12. Absorption in dielectric models

    CERN Document Server

    Churchill, R J

    2015-01-01

    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  13. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  14. Disorder-induced enhancement of indirect absorption in a GeSn photodetector grown by molecular beam epitaxy

    Science.gov (United States)

    Li, H.; Chang, C.; Cheng, H. H.; Sun, G.; Soref, R. A.

    2016-05-01

    We report an investigation on the absorption mechanism of a GeSn photodetector with 2.4% Sn composition in the active region. Responsivity is measured and absorption coefficient is calculated. Square root of absorption coefficient linearly depends on photon energy indicating an indirect transition. However, the absorption coefficient is found to be at least one order of magnitude higher than that of most other indirect materials, suggesting that the indirect optical absorption transition cannot be assisted only by phonon. Our analysis of absorption measurements by other groups on the same material system showed the values of absorption coefficient on the same order of magnitude. Our study reveals that the strong enhancement of absorption for the indirect optical transition is the result of alloy disorder from the incorporation of the much larger Sn atoms into the Ge lattice that are randomly distributed.

  15. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  16. The HI absorption 'Zoo'

    CERN Document Server

    Gereb, K; Morganti, R; Oosterloo, T A

    2014-01-01

    We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of widths, shapes and kinematical properties. We characterize the HI spectra of the individual detections using the busy function (Westmeier et al. 2014). With the goal of identifying different morphological structures of HI, we study the kinematical and radio source properties of the detections as function of their width. Narrow lines (FWHM = 500 km/s). These detections are good candidates for being HI outflows. The detection rate of HI outflows is 5 percent in the total radio AGN sample. This fraction represents a lower limit, however it could suggests that, if outflows are a characteristic phenomenon of all radio sources, they would have a short depletion timescale compared to the lifetime of the AGN. Blueshifted and broad/asymmetric lines are more often present among young...

  17. Examination of the relationship between riometer-derived absorption and the integral proton flux in the context of modeling polar cap absorption

    Science.gov (United States)

    Fiori, R. A. D.; Danskin, D. W.

    2016-11-01

    Energetic protons can penetrate into the ionosphere increasing ionization in the D region causing polar cap absorption that may potentially block high-frequency radio communications for transpolar flights. The protons are guided by the geomagnetic field into the high-latitude polar cap region. Riometers monitor variations in ionospheric absorption by observing the level of background cosmic radio noise. Current polar cap absorption modeling techniques are based on the linear relationship between absorption and the square root of the integral proton flux, which has previously only been demonstrated using data from a single high-latitude polar station. The proportionality constant describing this relationship is evaluated for two different polar cap absorption events occurring 7-11 March 2012 and 23 January 2012 to 1 February 2012. Examination of the proportionality constant using data from riometers distributed between 60° and 90° magnetic latitude reveals a previously unreported latitudinal dependence for data at magnetic latitudes of ≤66.8° on the dayside and ≤70.8° on the nightside. Incorporating the latitudinal dependence into the current D Region Absorption Prediction absorption model improves the agreement between measurement-derived and modeled parameters by increasing the correlation coefficient between data sets, reducing the root-mean-square error, and reducing the bias.

  18. Determinants and Polynomial Root Structure

    Science.gov (United States)

    De Pillis, L. G.

    2005-01-01

    A little known property of determinants is developed in a manner accessible to beginning undergraduates in linear algebra. Using the language of matrix theory, a classical result by Sylvester that describes when two polynomials have a common root is recaptured. Among results concerning the structure of polynomial roots, polynomials with pairs of…

  19. 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...

  20. Searching for Roots / Pierre Gervasoni

    Index Scriptorium Estoniae

    Gervasoni, Pierre

    1997-01-01

    Uuest heliplaadist "Searching for Roots. Eduard Tubin: Symphonie no 11; Arvo Pärt: Nekrolog-Symphonie no 1; Erkki-Sven Tüür: Searching for Roots - Insula deserta - Zeitraum; Orchestre philharmonique royal de Stockholm, Paavo Järvi (direction)" Virgin Classics 5 45212 2 (distribue par EMI)

  1. Project Work on Plant Roots.

    Science.gov (United States)

    Devonald, V. G.

    1986-01-01

    Methods of investigating plant root growth developed for research purposes can be adopted for student use. Investigations of the effect of water table level and of ethylene concentration are described, and techniques of measuring root growth are explained. (Author/ML)

  2. Modelling of trace metal uptake by roots taking into account complexation by exogenous organic ligands

    Science.gov (United States)

    Jean-Marc, Custos; Christian, Moyne; Sterckeman, Thibault

    2010-05-01

    The context of this study is phytoextraction of soil trace metals such as Cd, Pb or Zn. Trace metal transfer from soil to plant depends on physical and chemical processes such as minerals alteration, transport, adsorption/desorption, reactions in solution and biological processes including the action of plant roots and of associated micro-flora. Complexation of metal ions by organic ligands is considered to play a role on the availability of trace metals for roots in particular in the event that synthetic ligands (EDTA, NTA, etc.) are added to the soil to increase the solubility of the contaminants. As this role is not clearly understood, we wanted to simulate it in order to quantify the effect of organic ligands on root uptake of trace metals and produce a tool which could help in optimizing the conditions of phytoextraction.We studied the effect of an aminocarboxilate ligand on the absorption of the metal ion by roots, both in hydroponic solution and in soil solution, for which we had to formalize the buffer power for the metal. We assumed that the hydrated metal ion is the only form which can be absorbed by the plants. Transport and reaction processes were modelled for a system made up of the metal M, a ligand L and the metal complex ML. The Tinker-Nye-Barber model was adapted to describe the transport of solutes M, L and ML in the soil and absorption of M by the roots. This allowed to represent the interactions between transport, chelating reactions, absorption of the solutes at the root surface, root growth with time, in order to simulate metal uptake by a whole root system.Several assumptions were tested such as i) absorption of the metal by an infinite sink and according to a Michaelis-Menten kinetics, solutes transport by diffusion with and without ii) mass flow and iii) soil buffer power for the ligand L. In hydroponic solution (without soil buffer power), ligands decreased the trace metal flux towards roots, as they reduced the concentration of hydrated

  3. Adsorption of heavy metal from aqueous solution by dehydrated root powder of long-root Eichhornia crassipes.

    Science.gov (United States)

    Li, Qiang; Chen, Bo; Lin, Peng; Zhou, Jiali; Zhan, Juhong; Shen, Qiuying; Pan, Xuejun

    2016-01-01

    The root powder of long-root Eichhornia crassipes, as a new kind of biodegradable adsorbent, has been tested for aqueous adsorption of Pb, Zn, Cu, and Cd. From FT-IR, we found that the absorption peaks of phosphorous compounds, carbonyl, and nitrogenous compounds displayed obvious changes before and after adsorption which illustrated that plant characteristics may play a role in binding with metals. Surface properties and morphology of the root powders have been characterized by means of SEM and BET. Energy spectrum analysis showed that the metals were adsorbed on root powders after adsorption. Then, optimum quantity of powder, pH values, and metal ion concentrations in single-system and multi-system were detected to discuss the characteristics and mechanisms of metal adsorption. Freundlich model and the second-order kinetics equation could well describe the adsorption of heavy metals in single-metal system. The adsorption of Pb, Zn, and Cd in the multi-metal system decreased with the concentration increased. At last, competitive adsorption of every two metals on root powder proved that Cu and Pb had suppressed the adsorption performance of Cd and Zn.

  4. PEG-mediated osmotic stress induces premature differentiation of the root apical meristem and outgrowth of lateral roots in wheat.

    Science.gov (United States)

    Ji, Hongtao; Liu, Ling; Li, Kexue; Xie, Qingen; Wang, Zhijuan; Zhao, Xuhua; Li, Xia

    2014-09-01

    Water stress is one of the major environmental stresses causing growth retardation and yield loss of plants. In the past decades, osmotic adjustment, antioxidant protection, and stomatal movement have been extensively studied, but much less attention has been paid to the study of root system reprogramming to maximize water absorption and survival under water stress. Here, it is shown that polyethylene glycol (PEG)-simulated mild and moderate osmotic stress induced premature differentiation of the root apical meristem (RAM). It is demonstrated that RAM premature differentiation is a conserved adaptive mechanism that is widely adopted by various plants to cope with osmotic stress simulated by PEG 8000, and the occurrence of RAM premature differentiation is directly related to stress tolerance of plants. It is shown that the osmotic stress-induced premature differentiation caused growth cessation of primary roots allowing outgrowth of lateral roots. This work has uncovered a key mechanism for controlling the plastic development of the root system by which plants are capable of survival, growth, or reproduction under water stress.

  5. Cassava root membrane proteome reveals activities during storage root maturation.

    Science.gov (United States)

    Naconsie, Maliwan; Lertpanyasampatha, Manassawe; Viboonjun, Unchera; Netrphan, Supatcharee; Kuwano, Masayoshi; Ogasawara, Naotake; Narangajavana, Jarunya

    2016-01-01

    Cassava (Manihot esculenta Crantz) is one of the most important crops of Thailand. Its storage roots are used as food, feed, starch production, and be the important source for biofuel and biodegradable plastic production. Despite the importance of cassava storage roots, little is known about the mechanisms involved in their formation. This present study has focused on comparison of the expression profiles of cassava root proteome at various developmental stages using two-dimensional gel electrophoresis and LC-MS/MS. Based on an anatomical study using Toluidine Blue, the secondary growth was confirmed to be essential during the development of cassava storage root. To investigate biochemical processes occurring during storage root maturation, soluble and membrane proteins were isolated from storage roots harvested from 3-, 6-, 9-, and 12-month-old cassava plants. The proteins with differential expression pattern were analysed and identified to be associated with 8 functional groups: protein folding and degradation, energy, metabolism, secondary metabolism, stress response, transport facilitation, cytoskeleton, and unclassified function. The expression profiling of membrane proteins revealed the proteins involved in protein folding and degradation, energy, and cell structure were highly expressed during early stages of development. Integration of these data along with the information available in genome and transcriptome databases is critical to expand knowledge obtained solely from the field of proteomics. Possible role of identified proteins were discussed in relation with the activities during storage root maturation in cassava.

  6. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...... into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  7. The HI absorption "Zoo"

    Science.gov (United States)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1) detections, which are associated with gas-rich mergers, we find three new cases of profiles with blueshifted broad wings (with FW20 ≳ 500 km s-1) in high radio power AGN. These detections are good candidates for being HI outflows. Together with the known cases of outflows already included in the sample (3C 293 and

  8. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    XIANG FuYuan; LIANG ShunLin; LI AiGen

    2009-01-01

    The diffuse interstellar bands (DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s, the exact nature of DIBs still remains unclear. This article reviews the history of the detec-tions of DIBs in the Milky Way and external galaxies, the major observational characteristics of DIBs, the correlations or anti-correlations among DIBs or between DIBs and other interstellar features (e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise), and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  9. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The diffuse interstellar bands(DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s,the exact nature of DIBs still remains unclear. This article reviews the history of the detections of DIBs in the Milky Way and external galaxies,the major observational characteristics of DIBs,the correlations or anti-correlations among DIBs or between DIBs and other interstellar features(e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise),and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  10. 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)....

  11. [Responses of wheat seedlings root growth and leaf photosynthesis to drought stress].

    Science.gov (United States)

    Ma, Fu-Ju; Li, Dan-Dan; Cai, Jian; Jiang, Dong; Cao, Wei-Xing; Dai, Ting-Bo

    2012-03-01

    Taking drought-sensitive wheat cultivar Wangshuibai and drought-tolerance cultivar Luohan 7 as test materials, a hydroponic experiment was conducted to study the effects of drought stress on root system morphology, physiological characteristics and leaf photosynthesis of wheat seedlings, aimed to elucidate the adaptation mechanisms to drought stress. Under drought stress, the root vitality of the cultivars increased markedly, but the root number and root surface area decreased. Drought stress decreased relative water content and increased the ratio of bound water to free water in leaves of Wangshuibai, but had less effects on Luohan 7. Drought stress decreased, the leaf chlorophyll content, Pn g(s), Ci, and transpiration rate of the two cultivars, but had no significant effects on leaf chlorophyll content and Pn of Luohan 7. Drought stress decreased the leaf area of the two cultivars and the root biomass, shoot biomass, and plant biomass of Wangshuibai, but had no significant effects on Luohan 7. The results indicated that under drought stress, drought-tolerant wheat cultivar was able to compensate decreased root absorption area and retain higher root water uptake capability via enhancing root vitality and maintaining higher root biomass, and further, to keep higher leaf photosynthetic area and Pn to mitigate the inhibition of drought on wheat seedlings growth.

  12. Absorption intestinale des vitamines liposolubles

    OpenAIRE

    Reboul Emmanuelle

    2011-01-01

    The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fat...

  13. Absorption intestinale des vitamines liposolubles

    Directory of Open Access Journals (Sweden)

    Reboul Emmanuelle

    2011-03-01

    Full Text Available The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fatsoluble vitamin bioavailability.

  14. 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

  15. Ecological adaptation of Reaumuria soongorica root system architecture to arid environments

    Institute of Scientific and Technical Information of China (English)

    LiShan Shan; Yi Li; DongMei Geng; QiuLian Dong

    2014-01-01

    The architectural parameters of Reaumuria soongorica root system in different habitats of Gansu Province, China were analyzed to examine its ecological adaptability to arid environments. Results show that:(1) Topological indices of R. Soongorica root sys-tem are small in all habitats, and root branching pattern tends to be dichotomous. Also, the indices gradually increase in the Min-qin windblown sand region and the Zhangye Gobi region in Hexi Corridor, which indicates that drought tends to produce her-ringbone-like root branching patterns. (2) Fractal dimension values of R. Soongorica root system are small and not obvious in the Minqin windblown sand region and the Zhangye Gobi region in Hexi Corridor, with values of 1.1778 and 1.1169, respectively. Fractal dimension values are relatively large in Jiuzhoutai semi-arid hilly and gully region of the Loess Plateau, which indicates that the R. Soongorica root system has better fractal characteristics in this region than in the other regions. (3) Total branching ra-tios of the R. Soongorica root system in arid regions of Hexi Corridor are smaller than that in the Jiuzhoutai semi-arid hilly and gully region of the Loess Plateau. This shows that root branching ability in the semi-arid region is stronger, and it decreases to some degree with increased drought. (4) The root connection lengths of R. soongorica root system are long in all habitats, but there are significant length differences between the different habitats. The root connection length at the Minqin windblown sand region is the longest. It is concluded that R. soongorica adapts to arid environments by decreasing root branching, decreasing root overlap and increasing root connection length, which makes its root branching pattern tend to be herringbone-like to reduce com-petition in root internal environment for nutrients and to enhance root absorption rate of nutrients, and ensure effective nutrition space. Thus the roots can absorb enough water and nutrients

  16. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  17. Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In situ Rice Roots

    Science.gov (United States)

    The speciation and distribution of cobalt (Co) in soils is poorly understood. This study was conducted using X-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble Co(II) aging, submergence-dried cycling, and the presence of in vivo rice roots on the...

  18. Balancing Absorptive Capacity and Inbound Open Innovation for Sustained Innovative Performance

    DEFF Research Database (Denmark)

    Bongsun, Kim; Kim, Eonsoo; Foss, Nicolai Juul

    2016-01-01

    How can a firm develop new ideas and turn them into profitable innovations on a sustained basis? We address this fundamental issue in a novel way by developing an integrative framework of absorptive capacity (AC) and inbound open innovation that is rooted in the attention-based view of the firm. We...

  19. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains,...

  20. Multifunctional hybrids for electromagnetic absorption

    Energy Technology Data Exchange (ETDEWEB)

    Huynen, I. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Quievy, N. [Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bailly, C. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bollen, P. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Detrembleur, C. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium); Eggermont, S.; Molenberg, I. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Thomassin, J.M.; Urbanczyk, L. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium)

    2011-05-15

    Highlights: > EM absorption requires low dielectric constant and {approx}1 S/m electrical conductivity. > New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. > The EM absorption in the GHz range is superior to any known material. > A closed form model is used to guide the design of the hybrid. > The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  1. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  2. Absorption of copper(II) by creosote bush (Larrea tridentata): use of atomic and x-ray absorption spectroscopy.

    Science.gov (United States)

    Gardea-Torresdey, J L; Arteaga, S; Tiemann, K J; Chianelli, R; Pingitore, N; Mackay, W

    2001-11-01

    Larrea tridentata (creosote bush), a common North American native desert shrub, exhibits the ability to take up copper(II) ions rapidly from solution. Following hydroponic studies, U.S. Environmental Protection Agency method 200.3 was used to digest the plant samples, and flame atomic absorption spectroscopy (FAAS) was used to determine the amount of copper taken up in different parts of the plant. The amount of copper(II) found within the roots, stems, and leaves was 13.8, 1.1, and 0.6 mg/g, respectively, after the creosote bush was exposed to a 63.5-ppm copper(II) solution for 48 h. When the plant was exposed to a 635-ppm copper(II) solution, the roots, stems, and leaves contained 35.0, 10.5, and 3.8 mg/g, respectively. In addition to FAAS analysis, x-ray microfluorescence (XRMF) analysis of the plant samples provided further confirmation of copper absorption by the various plant parts. X-ray absorption spectroscopy (XAS) elucidated the oxidation state of the copper absorbed by the plants. The copper(II) absorbed from solution remained as copper(II) bound to oxygen-containing ligands within the plant samples. The results of this study indicate that creosote bush may provide a useful and novel method of removing copper(II) from contaminated soils in an environmentally friendly manner.

  3. Competitive sorption of heavy metals by water hyacinth roots.

    Science.gov (United States)

    Zheng, Jia-Chuan; Liu, Hou-Qi; Feng, Hui-Min; Li, Wen-Wei; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Yu, Han-Qing

    2016-12-01

    Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca(2+) and Mg(2+). However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry.

  4. Evaluation of absorption/stripping for second phase expansion of KG gas cracker

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-01

    This report addresses technology evaluation for a second phase expansion of BP Chemical Ltd.`s (BPCL) KG cracker. Its primary objective was to determine if the absorption/stripping technology being developed by BPCL is competitive with cryogenic demethanization technology. The expansion basis for this evaluation is a 150,000 MTA ethylene increment. This increment represents an increase in KG`s capacity from 450,000 MTA after the current expansion to an ultimate capacity of 600,000 MTA. Two recovery systems for a 150,000 MTA expansion are compared: (1) Case A - Absorption/Stripping Expansion; and (2) Case B - ARS Expansion. Another objective of this report was to confirm the magnitude of the economic advantages of the absorption/stripping technology for grass roots applications. For that evaluation, absorption/stripping was compared with the original 350,000 MTA KG recovery system. The two additional 350,000 MTA grass roots cases evaluated are: (1) Case C - Absorption/Stripping - Grass Roots Design; (2) Case D - Conventional Cryogenic Recovery (Original KG 350,000 MTA design).

  5. 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.

  6. Review on Mutation in Lateral Root of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xia; ZHANG Da; HAO Zaibin

    2011-01-01

    Rice roots include seminal roots, adventitious roots, lateral roots and root hairs, At present, progresses in the research of rice roots have been achieved in many aspects, such as root morphology, root activity, root reaction to various environmental factors as a contribution of root growth and rice yield, the relationship between root growth and stems/leaves/flowers/rice, genetic laws of root characters, etc. However, there are very few researches on lateral root mutant. This paper reviewed progresses of the lateral root mutant of rice from the perspectives of phytomorphology to plant physiology and biochemistry to the gene mapping, consisting of mechanism of developing lateral root of rice, gene cloning and functional analysis of lateral root development, the relationship between auxin and lateral roots, agronomic traits of lateral roots mutant, structure and morphology of root hairs, gravity anomaly of root, redox metabolism and proteomics researches of the mutation in lateral root of rice.

  7. How Can Science Education Foster Students' Rooting?

    Science.gov (United States)

    Østergaard, Edvin

    2015-01-01

    The question of how to foster rooting in science education points towards a double challenge; efforts to "prevent" (further) uprooting and efforts to "promote" rooting/re-rooting. Wolff-Michael Roth's paper discusses the uprooting/rooting pair of concepts, students' feeling of alienation and loss of fundamental sense of the…

  8. Gastrointestinal citrate absorption in nephrolithiasis

    Science.gov (United States)

    Fegan, J.; Khan, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    Gastrointestinal absorption of citrate was measured in stone patients with idiopathic hypocitraturia to determine if citrate malabsorption could account for low urinary citrate. Citrate absorption was measured directly from recovery of orally administered potassium citrate (40 mEq.) in the intestinal lavage fluid, using an intestinal washout technique. In 7 stone patients citrate absorption, serum citrate levels, peak citrate concentration in serum and area under the curve were not significantly different from those of 7 normal subjects. Citrate absorption was rapid and efficient in both groups, with 96 to 98% absorbed within 3 hours. The absorption of citrate was less efficient from a tablet preparation of potassium citrate than from a liquid preparation, probably due to a delayed release of citrate from wax matrix. However, citrate absorption from solid potassium citrate was still high at 91%, compared to 98% for a liquid preparation. Thus, hypocitraturia is unlikely to be due to an impaired gastrointestinal absorption of citrate in stone patients without overt bowel disease.

  9. Aluminium localization in root tips of the aluminium-accumulating plant species buckwheat (Fagopyrum esculentum Moench).

    Science.gov (United States)

    Klug, Benjamin; Specht, André; Horst, Walter J

    2011-11-01

    Aluminium (Al) uptake and transport in the root tip of buckwheat is not yet completely understood. For localization of Al in root tips, fluorescent dyes and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were compared. The staining of Al with morin is an appropriate means to study qualitatively the radial distribution along the root tip axis of Al which is complexed by oxalate and citrate in buckwheat roots. The results compare well with the distribution of total Al determined by LA-ICP-MS which could be reliably calibrated to compare with Al contents by conventional total Al determination using graphite furnace atomic absorption spectrometry. The Al localization in root cross-sections along the root tip showed that in buckwheat Al is highly mobile in the radial direction. The root apex predominantly accumulated Al in the cortex. The subapical root section showed a homogenous Al distribution across the whole section. In the following root section Al was located particularly in the pericycle and the xylem parenchyma cells. With further increasing distance from the root apex Al could be detected only in individual xylem vessels. The results support the view that the 10 mm apical root tip is the main site of Al uptake into the symplast of the cortex, while the subapical 10-20 mm zone is the main site of xylem loading through the pericycle and xylem parenchyma cells. Progress in the better molecular understanding of Al transport in buckwheat will depend on the consideration of the tissue specificity of Al transport and complexation.

  10. MES buffer affects Arabidopsis root apex zonation and root growth by suppressing superoxide generation in root apex

    Directory of Open Access Journals (Sweden)

    Tomoko eKagenishi

    2016-02-01

    Full Text Available In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species. MES, 2-(N-morpholinoethanesulfonic acid as one of the Good’s buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8. However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone. Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the reactive oxygen species (ROS homeostasis in root apex.

  11. Total light absorption in graphene

    CERN Document Server

    Thongrattanasiri, Sukosin; de Abajo, F Javier Garcia

    2011-01-01

    We demonstrate that 100% light absorption can take place in a single patterned sheet of doped graphene. General analysis shows that a planar array of small lossy particles exhibits full absorption under critical-coupling conditions provided the cross section of each individual particle is comparable to the area of the lattice unit-cell. Specifically, arrays of doped graphene nanodisks display full absorption when supported on a substrate under total internal reflection, and also when lying on a dielectric layer coating a metal. Our results are relevant for infrared light detectors and sources, which can be made tunable via electrostatic doping of graphene.

  12. Magnetophoretic Induction of Root Curvature

    Science.gov (United States)

    Hasenstein, Karl H.

    1997-01-01

    The last year of the grant period concerned the consolidation of previous experiments to ascertain that the theoretical premise apply not just to root but also to shoots. In addition, we verified that high gradient magnetic fields do not interfere with regular cellular activities. Previous results have established that: (1) intracellular magnetophoresis is possible; and (2) HGMF lead to root curvature. In order to investigate whether HGMF affect the assembly and/or organization of structural proteins, we examined the arrangement of microtubules in roots exposed to HGMF. The cytoskeletal investigations were performed with fomaldehyde-fixed, nonembedded tissue segments that were cut with a vibratome. Microtubules (MTs) were stained with rat anti-yeast tubulin (YOL 1/34) and DTAF-labeled antibody against rat IgG. Microfilaments (MFs) were visualized by incubation in rhodamine-labeled phalloidin. The distribution and arrangement of both components of the cytoskeleton were examined with a confocal microscope. Measurements of growth rates and graviresponse were done using a video-digitizer. Since HGMF repel diamagnetic substances including starch-filled amyloplasts and most The second aspect of the work includes studies of the effect of cytoskeletal inhibitors on MTs and MFs. The analysis of the effect of micotubular inhibitors on the auxin transport in roots showed that there is very little effect of MT-depolymerizing or stabilizing drugs on auxin transport. This is in line with observations that application of such drugs is not immediately affecting the graviresponsiveness of roots.

  13. 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.

  14. Capturing Arabidopsis Root Architecture Dynamics with root-fit Reveals Diversity in Responses to Salinity

    NARCIS (Netherlands)

    Julkowska, M.M.; Hoefsloot, H.C.J.; Mol, S.; Feron, R.; de Boer, G.J.; Haring, M.A.; Testerink, C.

    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 i

  15. Bent Electro-Absorption Modulator

    DEFF Research Database (Denmark)

    2002-01-01

    The present invention relates to a method and a device for modulating optical signals based on modulating bending losses in bend, quantum well semiconductor waveguide sections. The complex refractive index of the optical active semiconducting components of the waveguide section is modulated...... components and the applied electric field in relation to the frequency of the modulated radiation, the bending losses (and possibly coupling losses) will provide extinction of light guided by the bent waveguide section. The refractive index contract may be modulated while keeping the absorption coefficient...... substantially constant and small, whereby the guided light can be modulated only by bending losses. Alternatively, the invention may be applied to enhance the extinction ratio of existing absorption modulators such as Electro-Absorption Modulators (EAMs) in which case extinction by absorption and extinction...

  16. Circadian Regulation of Macronutrient Absorption.

    Science.gov (United States)

    Hussain, M Mahmood; Pan, Xiaoyue

    2015-12-01

    Various intestinal functions exhibit circadian rhythmicity. Disruptions in these rhythms as in shift workers and transcontinental travelers are associated with intestinal discomfort. Circadian rhythms are controlled at the molecular level by core clock and clock-controlled genes. These clock genes are expressed in intestinal cells, suggesting that they might participate in the circadian regulation of intestinal functions. A major function of the intestine is nutrient absorption. Here, we will review absorption of proteins, carbohydrates, and lipids and circadian regulation of various transporters involved in their absorption. A better understanding of circadian regulation of intestinal absorption might help control several metabolic disorders and attenuate intestinal discomfort associated with disruptions in sleep-wake cycles.

  17. 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.

  18. 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...

  19. Effects of ridge tillage on photosynthesis and root characters of rice

    Directory of Open Access Journals (Sweden)

    Yao Yuan-zhi

    2015-03-01

    Full Text Available Rice (Oryza sativa L. is an important crop and breeding has not been able to improve yield. Root characteristics of hybrid rice 'Zhuliangyou 02' under conventional tillage and ridge tillage were studied in a Calcisols in Huaihua, China, from 2011 to 2013 to find better tillage methods to resolve massive water consumption, improve yield, and enhance productivity of agricultural labor for rice cultivation. Results showed ridge tillage increased photosynthetic parameters such as photosynthetic rate (P N, stomatal conductance (g s, and water use efficiency (WUE. It also significantly enhanced rice root number, root activity, and antioxidant enzyme activities; it also increased effective panicle number and actual yield by 22.12% and 15.18%, respectively, and enhanced aerenchymae during the early growth stage. Overall, ridge tillage could promote hybrid rice yields by enhancing root absorption, gas exchange, and reducing water consumption. It could be widely used in rice cultivation.

  20. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

    Directory of Open Access Journals (Sweden)

    Frédéric eDanjon

    2013-10-01

    Full Text Available Root systems of woody plants generally display a strong relationship between the cross-sectional area (CSA 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 that 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 for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available.We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 yr from a stand. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots.CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots.The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

  1. OZONE ABSORPTION IN RAW WATERS

    Directory of Open Access Journals (Sweden)

    LJILJANA TAKIĆ

    2008-03-01

    Full Text Available The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR. A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption.

  2. Absorption Of Dietary Lipid Components

    OpenAIRE

    Abdulkadir Hurşit

    2015-01-01

    Although the digestion and absorption of lipids that are necessary for the survival of living organisms are well known in general terms, nevertheless how different lipids to be digested, how it is distributed into the bloodstream, and how to be used by the cells, are unknown issues by most non specialist people. In recent years, knowledge of lipid digestion and absorption has expanded considerably. More insight has been gained in the mechanism of action of H + pump as a transport system in fa...

  3. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  4. Grass Roots War on Poverty

    OpenAIRE

    Amsden, Alice H

    2012-01-01

    Sub-Saharan Africa’s failure to slay the dragon of poverty is due to a logical flaw in its policies: the remedies to reduce poverty don’t address the causes. Poverty is caused by unemployment, owing to a scarcity of jobs that pay above bare subsistence, but grass-roots poverty alleviation measures are exclusively designed to make job-seekers more capable although no jobs are available. The ‘appropriate’ technologies of the grass roots movement that dominates anti-poverty policies are ...

  5. [Determination of inorganic elements in different parts of Sonchus oleraceus L by flame atomic absorption spectrometry].

    Science.gov (United States)

    Wang, Nai-Xing; Cui, Xue-Gui; Du, Ai-Qin; Mao, Hong-Zhi

    2007-06-01

    Flame atomic absorption spectrometry with air-acetylene flame was used for the determination of inorganic metal elements in different parts ( flower, leaf, stem and root) of Sonchus oleraceus L. The contents of Ca, Mg, K, Na, Fe, Mn, Cu, Zn, Cr, Co, Ni, Pb and Cd in the flower, leaf, stem and root of Sonchus oleraceus L were compared. The order from high to low of the additive weight (microg x g(-1)) for the 13 kinds of metal elements is as follows: leaf (77 213.72) > flower (47 927.15) > stem(42 280.99) > root (28 131.18). From the experimental results it was found that there were considerable differences in the contents of the metal elements in different parts, and there were richer contents of Fe, Zn, Mn and Cu in root and flower, which are necessary to human health, than in other parts.

  6. Fat-soluble vitamin intestinal absorption: absorption sites in the intestine and interactions for absorption.

    Science.gov (United States)

    Goncalves, Aurélie; Roi, Stéphanie; Nowicki, Marion; Dhaussy, Amélie; Huertas, Alain; Amiot, Marie-Josèphe; Reboul, Emmanuelle

    2015-04-01

    The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption.

  7. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    Science.gov (United States)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  8. Four cuspal maxillary second premolar with single root and three root canals: Case report

    Directory of Open Access Journals (Sweden)

    Parul Bansal

    2016-01-01

    Full Text Available Traditional configuration of maxillary second premolars has been described to have two cusps, one root and one or two root canals. The endodontic literature reports considerable anatomic aberrations in the root canal morphology of maxillary second premolar but the literature available on the variation in cuspal anatomy and its relationship to the root canal anatomy is sparse. The purpose of this clinical report was to describe the root and root canal configuration of a maxillary second premolar with four cusps.

  9. Application of Electrical Resistivity Tomography for Detecting Root Biomass in Coffee Trees

    Directory of Open Access Journals (Sweden)

    Carlos Mauricio Paglis

    2013-01-01

    Full Text Available Roots play an important role in plants and are responsible for several functions; among them are anchorage and nutrient and water absorption. Several methodologies are being tested and used to study plant root systems in order to avoid destructive root sampling. Electrical resistivity tomography is among these methodologies. The aim of this preliminary study was to use electrical resistivity for detecting root biomass in coffee trees. Measurements were performed in a soil transect with an ABM AL 48-b resistivimeter with a pole-dipole configuration. The tomograms indicated variability in soil resistivity values ranging from 120 to 1400 Ω·m−1. At the first 0.30 cm soil layer, these values were between 267 and 952 Ω·m−1. Oriented by this result, root samples were taken at 0.10, 0.20, and 0.30 m depths within 0.50 m intervals along the soil transect to compare soil resistivity with root mass density (RMD. RMD data, up to this depth, varied from 0.000019 to 0.009469 Mg·m−3, showing high spatial variability and significant relationship to the observed values of soil resistivity. These preliminary results showed that the electrical resistivity tomography can contribute to root biomass studies in coffee plants; however, more experiments are necessary to confirm the found results in Brazil coffee plantations.

  10. ALFIN-LIKE 6 is involved in root hair elongation during phosphate deficiency in Arabidopsis.

    Science.gov (United States)

    Chandrika, Nulu Naga Prafulla; Sundaravelpandian, Kalaipandian; Yu, Su-May; Schmidt, Wolfgang

    2013-05-01

    Phosphate (Pi) starvation in plants induces dense and elongated root hairs, which increase the absorptive surface area of the roots and play a critical role in Pi uptake. The molecular mechanism underlying these changes remains unclear. Forward and reverse genetic approaches were employed to identify novel genes involved in root hair formation on Pi starvation. The mutant per2, with defects in root hair elongation specifically under low Pi conditions, was identified in a large-scale genetic screen of T-DNA insertion lines. The phenotype was caused by a mutation in the homeodomain protein ALFIN-LIKE 6 (AL6). From a screen of mutants defective in genes that showed lower transcript abundance in per2 relative to wild-type roots on low Pi medium, we identified four putative downstream targets of AL6, namely ETC1, NPC4, SQD2 and PS2, all of which were critical in root hair elongation of Pi-deficient plants. The results further indicate that AL6 is involved in the control of growth and several key responses to Pi starvation. Our findings demonstrate that AL6 controls the transcription of a suite of genes critical for root hair elongation under low Pi conditions, suggesting a novel physiological function for an Alfin gene in Arabidopsis.

  11. The Roots of School Leadership.

    Science.gov (United States)

    Sergiovanni, Thomas J.

    1994-01-01

    The Pyramid, Railroad, and High Performance theories of leadership are inappropriate for school settings. At root, school leadership is about connecting people morally to each other and to their work. The work of leadership involves developing shared purposes, beliefs, values, and conceptions associated with teaching and learning,…

  12. Cutting the Roots of Violence.

    Science.gov (United States)

    Koziey, Paul W.

    1996-01-01

    Violence is rooted in obedience to authority and in comparisons--foundations of our institutions of parenting and schooling. Obedience brings reward and punishment, comparison perpetuates a cycle of competition and conflict. Television violence is especially harmful because children easily understand visual images. The Reality Research approach to…

  13. Disease notes - Bacterial root rot

    Science.gov (United States)

    Bacterial root rot initiated by lactic acid bacteria, particularly Leuconostoc, occurs every year in Idaho sugarbeet fields. Hot fall weather seems to make the problem worse. Although Leuconostoc initiates the rot, other bacteria and yeast frequently invade the tissue as well. The acetic acid bac...

  14. [Effects nutrients on the seedlings root hair development and root growth of Poncirus trifoliata under hydroponics condition].

    Science.gov (United States)

    Cao, Xiu; Xia, Ren-Xue; Zhang, De-Jian; Shu, Bo

    2013-06-01

    Ahydroponics experiment was conducted to study the effects of nutrients (N, P, K, Ca, Mg, Fe, and Mn) deficiency on the length of primary root, the number of lateral roots, and the root hair density, length, and diameter on the primary root and lateral roots of Poncirus trifoliata seedlings. Under the deficiency of each test nutrient, root hair could generate, but was mainly concentrated on the root base and fewer on the root tip. The root hair density on lateral roots was significantly larger than that on primary root, but the root hair length was in adverse. The deficiency of each test nutrient had greater effects on the growth and development of root hairs, with the root hair density on primary root varied from 55.0 to 174.3 mm(-2). As compared with the control, Ca deficiency induced the significant increase of root hair density and length on primary root, P deficiency promoted the root hair density and length on the base and middle part of primary root and on the lateral roots significantly, Fe deficiency increased the root hair density but decreased the root hair length on the tip of primary root significantly, K deficiency significantly decreased the root hair density, length, and diameter on primary root and lateral roots, whereas Mg deficiency increased the root hair length of primary root significantly. In all treatments of nutrient deficiency, the primary root had the similar growth rate, but, with the exceptions of N and Mg deficiency, the lateral roots exhibited shedding and regeneration.

  15. Measuring the efficacy of a root biobarrier with x-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tollner, E.W.; Murphy, C.E. Jr. (Georgia Univ., Griffin, GA (USA). Dept. of Agricultural Engineering)

    1990-08-16

    X-ray computed tomography is a useful tool for investigating soil physical properties nondestructively. There is a need to develop proper calibration relationships between soil properties and the x-ray absorption coefficient. The objective of the work was to evaluate soil factors affecting the x-ray absorption coefficient. Based on a theoretical analysis, experimental data from five soils and on results of several other investigators, it was concluded that for many applications, one calibration relationship is applicable to a wide range of soils. The montmorillinitic clay used in the study required special handling due to the extreme shrinkage of this soil upon drying. Knowledge of chemical composition enables approximations but not exact predictions of the x-ray absorption coefficient. The results suggested some reasonable alternative to exhaustive calibration for each anticipated soil condition. Quantification of root activity in terms of root growth and indirectly through water uptake is necessary for understanding plant growth dynamics. X-ray computed tomography (CT) enables qualitative as well as two quantitative outputs, one of which can lead to conclusions regarding root activity. A greenhouse study involving soil columns (Lakeland sand, bulk density 1.4 Mg/m{sup 3}) planted to soybean, Bahiagras, and control (no vegetation) was conducted in 1989. A treflan based on chemical barrier was placed in half of the soil column of each species. The mean x-ray absorption correlated to water content. Results suggested that root presence can also be indirectly inferred based on water content drawn down during planned stress events. It was concluded that x-ray CT may have a niche in soil-water-plant relation studies, particularly when plant species have large roots. 35 refs., 13 figs., 8 tabs.

  16. Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1989-01-01

    Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

  17. Effects and mechanisms of the combined pollution of lanthanum and acid rain on the root phenotype of soybean seedlings.

    Science.gov (United States)

    Sun, Zhaoguo; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2013-09-01

    Rare earth pollution and acid rain pollution are both important environmental issues worldwide. In regions which simultaneously occur, the combined pollution of rare earth and acid rain becomes a new environmental issue, and the relevant research is rarely reported. Accordingly, we investigated the combined effects and mechanisms of lanthanum ion (La(3+)) and acid rain on the root phenotype of soybean seedlings. The combined pollution of low-concentration La(3+) and acid rain exerted deleterious effects on the phenotype and growth of roots, which were aggravated by the combined pollution of high-concentration La(3+) and acid rain. The deleterious effects of the combined pollution were stronger than those of single La(3+) or acid rain pollution. These stronger deleterious effects on the root phenotype and growth of roots were due to the increased disturbance of absorption and utilization of mineral nutrients in roots.

  18. Mapping tree root system in dikes using induced polarization: Focus on the influence of soil water content

    Science.gov (United States)

    Mary, Benjamin; Saracco, Ginette; Peyras, Laurent; Vennetier, Michel; Mériaux, Patrice; Camerlynck, Christian

    2016-12-01

    In this study, we assessed induced polarization as potential non-destructive method for root detection in dike embankments. We used both laboratory and field experiment to describe the electrical signal with a focus on soil water content. Our objective was to determine in which hydric state of the soil, and related electrical properties, roots could be accurately discriminated. We hypothesized that preferential water zone absorption near the roots could, in some conditions, contribute to locate them. During the laboratory experiments, we compared the response of containers filled with the same homogeneous silty clay bare material, and without (A) or with freshly cut root (B) at different levels of soil water content. Resistivity and phase variations with soil water content indicated that it was preferable to work in dry conditions since the contrast was higher. Interactions and overlapping between polarization effects of both root and soil made it difficult to interpret first chargeability maps. This led us to study temporal-spatial variations by considering the dynamics of water absorption during a field experiment. High resolution time lapses images showed a correlation between root location and complex resistivity anomalies. Although these first results have to be confirmed by further measurements, induced polarization seems to add useful information to interpret anomalies produced by woody roots.

  19. Arsenic rich iron plaque on macrophyte roots - an ecotoxicological risk?

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, M.A. [School of Biological Sciences, University of Aberdeen, Cruickshank Bld, St Machar Drive, Aberdeen, AB24 3UU (United Kingdom); Instituto de Investigacion en Recursos Cinegeticos, IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain)], E-mail: mark.taggart@uclm.es; Mateo, R. [Instituto de Investigacion en Recursos Cinegeticos, IREC (CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain); Charnock, J.M.; Bahrami, F. [Synchrotron Radiation Department, CCLRC Daresbury Laboratory, Warrington, Cheshire, WA4 4AD (United Kingdom); Green, A.J. [Department of Wetland Ecology, Estacion Biologica de Donana, CSIC, Pabellon del Peru, Avenida Maria Luisa s/n, 41013 Seville (Spain); Meharg, A.A. [School of Biological Sciences, University of Aberdeen, Cruickshank Bld, St Machar Drive, Aberdeen, AB24 3UU (United Kingdom)

    2009-03-15

    Arsenic is known to accumulate with iron plaque on macrophyte roots. Three to four years after the Aznalcollar mine spill (Spain), residual arsenic contamination left in seasonal wetland habitats has been identified in this form by scanning electron microscopy. Total digestion has determined arsenic concentrations in thoroughly washed 'root + plaque' material in excess of 1000 mg kg{sup -1}, and further analysis using X-ray absorption spectroscopy suggests arsenic exists as both arsenate and arsenite. Certain herbivorous species feed on rhizomes and bulbs of macrophytes in a wide range of global environments, and the ecotoxicological impact of consuming arsenic rich iron plaque associated with such food items remains to be quantified. Here, greylag geese which feed on Scirpus maritimus rhizome and bulb material in areas affected by the Aznalcollar spill are shown to have elevated levels of arsenic in their feces, which may originate from arsenic rich iron plaque. - Accumulation of metals with iron plaque on macrophyte roots in wetlands poses an ecotoxicological risk to certain herbivores.

  20. Absorption characteristics of bacteriorhodopsin molecules

    Indian Academy of Sciences (India)

    H K T Kumar; K Appaji Gowda

    2000-03-01

    The bacteriorhodopsin molecule absorbs light and undergoes a series of structural transformation following a well-defined photocycle. The complex photocycle is transformed to an equivalent level diagram by considering the lifetime of the intermediate states. Assuming that only and states are appreciably populated at any instant of time, the level diagram is further simplified to two-level system. Based on the rate equations for two-level system, an analytic expression for the absorption coefficient of bacteriorhodopsin molecule is derived. It is applied to study the behaviour of absorption coefficient of bacteriorhodopsin film in the visible wavelength region of 514 nm. The dependence of absorption coefficient of bacteriorhodopsin film on the thickness of the film, total number density of active molecules and initial number density of molecules in -state is presented in the graphical form.

  1. Dynamics of heterorhizic root systems: protoxylem groups within the fine-root system of Chamaecyparis obtusa.

    Science.gov (United States)

    Hishi, Takuo; Takeda, Hiroshi

    2005-08-01

    To understand the physiology of fine-root functions in relation to soil organic sources, the heterogeneity of individual root functions within a fine-root system requires investigation. Here the heterogeneous dynamics within fine-root systems are reported. The fine roots of Chamaecyparis obtusa were sampled using a sequential ingrowth core method over 2 yr. After color categorization, roots were classified into protoxylem groups from anatomical observations. The root lengths with diarch and triarch groups fluctuated seasonally, whereas the tetrarch root length increased. The percentage of secondary root mortality to total mortality increased with increasing amounts of protoxylem. The carbon : nitrogen ratio indicated that the decomposability of primary roots might be greater than that of secondary roots. The position of diarch roots was mostly apical, whereas tetrarch roots tended to be distributed in basal positions within the root architecture. We demonstrate the heterogeneous dynamics within a fine-root system of C. obtusa. Fine-root heterogeneity should affect soil C dynamics. This heterogeneity is determined by the branching position within the root architecture.

  2. Meromorphic iterative roots of linear fractional functions

    Institute of Scientific and Technical Information of China (English)

    SHI YongGuo; CHEN Li

    2009-01-01

    Iterative root problem can be regarded as a weak version of the problem of embedding a homeomorphism into a flow. There are many results on iterative roots of monotone functions. However, this problem gets more difficult in non-monotone cases. Therefore, it is interesting to find iterative roots of linear fractional functions (abbreviated as LFFs), a class of non-monotone functions on R. In this paper, iterative roots of LFFs are studied on C. An equivalence between the iterative functional equation for non-constant LFFs and the matrix equation is given. By means of a method of finding matrix roots, general formulae of all meromorphic iterative roots of LFFs are obtained and the precise number of roots is also determined in various cases. As applications, we present all meromorphic iterative roots for functions z and 1/z.

  3. Diabetic lipohypertrophy delays insulin absorption.

    Science.gov (United States)

    Young, R J; Hannan, W J; Frier, B M; Steel, J M; Duncan, L J

    1984-01-01

    The effect of lipohypertrophy at injection sites on insulin absorption has been studied in 12 insulin-dependent diabetic patients. The clearance of 125I-insulin from sites with lipohypertrophy was significantly slower than from complementary nonhypertrophied sites (% clearance in 3 h, 43.8 +/- 3.5 +/- SEM) control; 35.3 +/- 3.9 lipohypertrophy, P less than 0.05). The degree of the effect was variable but sufficient in several patients to be of clinical importance. Injection-site lipohypertrophy is another factor that modifies the absorption of subcutaneously injected insulin.

  4. Quasistellar Objects Intervening Absorption Lines

    CERN Document Server

    Charlton, J C; Charlton, Jane C.; Churchill, Christopher W.

    2000-01-01

    We briefly review, at a level appropriate for graduate students and non-specialists, the field of quasar absorption lines (QALs). Emphasis is on the intervening absorbers. We present the anatomy of a quasar spectrum due to various classes of intervening absorption systems, and a brief historical review of each absorber class (Lyman-alpha forest and Lyman limit systems, and metal-line and damped Lyman-alpha absorbers). We also provide several heuristic examples on how the physical properties of both the intergalactic medium and the gaseous environments associated with earlier epoch galaxies can be inferred from QALs. The evolution of these environments from z=4 are discussed.

  5. Single-rooted primary first mandibular molar

    OpenAIRE

    Haridoss, SelvaKumar; Swaminathan, Kavitha; Rajendran, Vijayakumar; Rajendran, Bharathan

    2014-01-01

    Morphological variations like single-rooted molar in primary dentition are scarce. Understanding the root canal anatomy and variations is necessary for successful root canal therapy. The purpose of the present article is to report successful endodontic treatment of primary left mandibular first molar with an abnormal morphology of a single root. This case report highlights the importance of knowledge and its applications in the management of anomalous anatomic variants which play a crucial ro...

  6. Arbuscular mycorrhizal fungal colonization of Glycyrrhiza glabra roots enhances plant biomass, phosphorus uptake and concentration of root secondary metabolites

    Institute of Scientific and Technical Information of China (English)

    HongLing LIU; Yong TAN; Monika NELL; Karin ZITTER-EGLSEER; Chris WAWSCRAH; Brigitte KOPP; ShaoMing WANG; Johannes NOVAK

    2014-01-01

    Arbuscular mycorrhizal (AM) fungi penetrate the cortical cells of the roots of vascular plants, and are widely distributed in soil. The formation of these symbiotic bodies accelerates the absorption and utilization of min-eral elements, enhances plant resistance to stress, boosts the growth of plants, and increases the survival rate of transplanted seedlings. We studied the effects of various arbuscular mycorrhizae fungi on the growth and devel-opment of licorice (Glycyrrhiza glabra). Several species of AM, such as Glomus mosseae, Glomus intraradices, and a mixture of fungi (G. mosseae, G. intraradices, G. cladoideum, G. microagregatum, G. caledonium and G. etunica-tum) were used in our study. Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi, plant dry biomass, phosphorus concentration and concentration of secondary metabolites. We estab-lished two cloned strains of licorice, clone 3 (C3) and clone 6 (C6) to exclude the effect of genotypic variations. Our results showed that the AM fungi could in fact increase the leaf and root biomass, as well as the phosphorus con-centration in each clone. Furthermore, AM fungi significantly increased the yield of certain secondary metabolites in clone 3. Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants. There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots.

  7. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  8. The rhizosphere revisited: root microbiomics

    Directory of Open Access Journals (Sweden)

    Peter A.H.M. Bakker

    2013-05-01

    Full Text Available The rhizosphere was defined over 100 years ago as the zone around the root where microorganisms and processes important for plant growth and health are located. Recent studies show that the diversity of microorganisms associated with the root system is enormous. This rhizosphere microbiome extends the functional repertoire of the plant beyond imagination. The rhizosphere microbiome of Arabidopsis thaliana is currently being studied for the obvious reason that it allows the use of the extensive toolbox that comes with this model plant. Deciphering plant traits that drive selection and activities of the microbiome is now a major challenge in which Arabidopsis will undoubtedly be a major research object. Here we review recent microbiome studies and discuss future research directions and applicability of the generated knowledge

  9. Automatic Schema Evolution in Root

    Institute of Scientific and Technical Information of China (English)

    ReneBrun; FonsRademakers

    2001-01-01

    ROOT version 3(spring 2001) supports automatic class schema evolution.In addition this version also produces files that are self-describing.This is achieved by storing in each file a record with the description of all the persistent classes in the file.Being self-describing guarantees that a file can always be read later,its structure browsed and objects inspected.also when the library with the compiled code of these classes is missing The schema evolution mechanism supports the frequent case when multiple data sets generated with many different class versions must be analyzed in the same session.ROOT supports the automatic generation of C++ code describing the data objects in a file.

  10. Doubling bialgebras of rooted trees

    Science.gov (United States)

    Mohamed, Mohamed Belhaj; Manchon, Dominique

    2017-01-01

    The vector space spanned by rooted forests admits two graded bialgebra structures. The first is defined by Connes and Kreimer using admissible cuts, and the second is defined by Calaque, Ebrahimi-Fard and the second author using contraction of trees. In this article, we define the doubling of these two spaces. We construct two bialgebra structures on these spaces which are in interaction, as well as two related associative products obtained by dualization. We also show that these two bialgebras verify a commutative diagram similar to the diagram verified Calaque, Ebrahimi-Fard and the second author in the case of rooted trees Hopf algebra, and by the second author in the case of cycle-free oriented graphs.

  11. Rooting of microcuttings: Theory and practice

    NARCIS (Netherlands)

    Klerk, de G.J.M.

    2002-01-01

    Poor adventitious root formation is a major obstacle in micropropagation and in conventional propagation. This paper reviews recent progress in the understanding of adventitious root formation as a developmental process focusing on the role of plant hormones and on the effect of rooting conditions o

  12. Counting Rooted Nearly 2-regular Planar Maps

    Institute of Scientific and Technical Information of China (English)

    郝荣霞; 蔡俊亮

    2004-01-01

    The number of rooted nearly 2-regular maps with the valency of rootvertex, the number of non-rooted vertices and the valency of root-face as three parameters is obtained. Furthermore, the explicit expressions of the special cases including loopless nearly 2-regular maps and simple nearly 2-regular maps in terms of the above three parameters are derived.

  13. 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...... intensified cropping systems using chemical and mechanical inputs also show that facilitative interactions definitely can be of significance. It is concluded that a better understanding of the mechanisms behind facilitative interactions may allow us to benefit more from these phenomena in agriculture...

  14. Archimedes' calculations of square roots

    CERN Document Server

    Davies, E B

    2011-01-01

    We reconsider Archimedes' evaluations of several square roots in 'Measurement of a Circle'. We show that several methods proposed over the last century or so for his evaluations fail one or more criteria of plausibility. We also provide internal evidence that he probably used an interpolation technique. The conclusions are relevant to the precise calculations by which he obtained upper and lower bounds on pi.

  15. Evaluation of bacterial leakage of four root- end filling materials: Gray Pro Root MTA, White Pro Root MTA, Root MTA and Portland Cement (type I

    Directory of Open Access Journals (Sweden)

    Zarabian M.

    2005-07-01

    Full Text Available Background and Aim: Today several materials have been used for root- end filling in endodontic surgery. Optimal properties of Pro Root MTA in in-vitro and in-vivo studies has been proven. On the other hand, based on some studies, Root MTA (Iranian Pro Root MTA and Portland cement are similar to Pro Root MTA in physical and biologic properties. The aim of this study was to evaluate bacterial leakage (amount and mean leakage time of four root- end filling materials. Materials and Methods: In this experimental in-vitro study, seventy six extracted single- rooted human teeth were randomly divided into six groups for root-end filling with gray Pro Root MTA, white Pro Root MTA, Root MTA (Iranian Pro Root MTA, Portland Cement (type I and positive and negative control groups. Root canals were instrumented using the step- back technique. Root- end filling materials were placed in 3mm ultra sonic retro preparations. Samples and microleakage model system were sterilized in autoclave. The apical 3-4 mm of the roots were immersed in phenol red with 3% lactose broth culture medium. The coronal access of each specimen was inoculated every 24h with a suspension of Streptococcus sanguis (ATCC 10556. Culture media were observed every 24h for colour change indicating bacterial contamination for 60 days. Statistical analysis was performed using log- rank test with P<0.05 as the limit of significance. Results: At the end of study 50%, 56.25%, 56.25% and 50% of specimens filled with Gray Pro Root MTA, White Pro Root MTA. Root MTA and Portland Cement (type I had evidence of leakage respectively. The mean leakage time was 37.19±6.29, 36.44±5.81, 37.69±5.97 and 34.81±6.67 days respectively. Statistical analysis of data showed no significant difference among the leakage (amount and mean leakage time of the four tested root- end filling materials (P=0.9958. Conclusion: Based on the results of this study, there were no significant differences in leakage among the four

  16. Printing Values In Interactive ROOT

    CERN Document Server

    Perovic, Boris

    2015-01-01

    This project report summarizes the work I have been performing during the past twelve weeks as a Summer Student intern working on ROOT project in the SFT group, PH department, under the supervision of Axel Naumann and Danilo Piparo. One of the widely requested features for ROOT was improved interactive shell experience as well as improved printing of object values. Solving this issue was the goal of this project. Primarily, we have enabled printing of the collections. Secondly, we have unified the printing interface, making it much more robust and extendible. Thirdly, we have implemented printing of nested collections in a flexible and user-friendly manner. Finally, we have added an interactive mode, allowing for paginated output. At the beginning of the report, ROOT is presented with examples of where it is used and how important it is. Then, the motivation behind the project is elaborated, by presenting the previous state of the software package and its potential for improvement. Further, the process in wh...

  17. ROOT Status and Future Developments

    CERN Document Server

    Brun, R; Canal, P; Rademakers, Fons; Goto, Masaharu; Canal, Philippe; Brun, Rene

    2003-01-01

    In this talk we will review the major additions and improvements made to the ROOT system in the last 18 months and present our plans for future developments. The additons 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 templated 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, we intend to continue the development of PROOF and...

  18. Phene synergism between root hair length and basal root growth angle for phosphorus acquisition.

    Science.gov (United States)

    Miguel, Magalhaes Amade; Postma, Johannes Auke; Lynch, Jonathan Paul

    2015-04-01

    Shallow basal root growth angle (BRGA) increases phosphorus acquisition efficiency by enhancing topsoil foraging because in most soils, phosphorus is concentrated in the topsoil. Root hair length and density (RHL/D) increase phosphorus acquisition by expanding the soil volume subject to phosphorus depletion through diffusion. We hypothesized that shallow BRGA and large RHL/D are synergetic for phosphorus acquisition, meaning that their combined effect is greater than the sum of their individual effects. To evaluate this hypothesis, phosphorus acquisition in the field in Mozambique was compared among recombinant inbred lines of common bean (Phaseolus vulgaris) having four distinct root phenotypes: long root hairs and shallow basal roots, long root hairs and deep basal roots, short root hairs and shallow basal roots, and short root hairs and deep basal roots. The results revealed substantial synergism between BRGA and RHL/D. Compared with short-haired, deep-rooted phenotypes, long root hairs increased shoot biomass under phosphorus stress by 89%, while shallow roots increased shoot biomass by 58%. Genotypes with both long root hairs and shallow roots had 298% greater biomass accumulation than short-haired, deep-rooted phenotypes. Therefore, the utility of shallow basal roots and long root hairs for phosphorus acquisition in combination is twice as large as their additive effects. We conclude that the anatomical phene of long, dense root hairs and the architectural phene of shallower basal root growth are synergetic for phosphorus acquisition. Phene synergism may be common in plant biology and can have substantial importance for plant fitness, as shown here.

  19. The quality of root fillings remaining in mandibular incisors after root-end cavity preparation

    NARCIS (Netherlands)

    Wu, MK; de Schwartz, FBC; van der Sluis, LWM; Wesselink, PR

    2001-01-01

    Aim The aim of this study was to determine the quality of root fillings remaining in mandibular incisors after root-end resection and root-end cavity preparation. Methodology Roots of 40 mandibular incisors. 12 mm in length. were divided into two groups and instrumented using a balanced force techni

  20. Using coloured roots to study root interaction and competition in intercropped legumes and non-legumes

    DEFF Research Database (Denmark)

    Tosti, Giacomo; Thorup-Kristensen, Kristian

    2010-01-01

    if a species with coloured roots can be used to examine the interaction in a legume-non-legume intercropping system; (ii) to verify the importance of initial root growth on the successive root development of mixture component plants; (iii) to test if the root interaction in the shallow layers has consequences...

  1. Exercise, Intestinal Absorption, and Rehydration

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ KEYPOINTS 1. The proximal small intestine (duodenum & jejunum) is the primary site of fluid absorption. It absorbs about 50% to 60% of any given fluid load. The colon or large intestine absorbs approximately 80 to 90% of the fluid it receives, but accounts for only about 15% of the total fluid load.

  2. Migrant labor absorption in Malaysia.

    Science.gov (United States)

    Nayagam, J

    1992-01-01

    The use of migrant workers to ease labor shortages caused by rapid industrialization in Malaysia during the twentieth century is examined. "This paper will focus on: (1) the extent, composition and distribution of migrant workers; (2) the labor shortage and absorption of migrant workers; and (3) the role of migrant workers in the government's economic restructuring process."

  3. Neutron Absorption in Geological Material

    Science.gov (United States)

    Løvhøiden, G.; Andersen, E.

    1990-01-01

    Thermal neutron absorption cross section of geological samples is determined with the steady state neutron source method. Cross section measurements of North Sea sediments demonstrate that also materials with high contents of clay minerals may be investigated with the steady state method.

  4. Oxygen Absorption in Cooling Flows.

    Science.gov (United States)

    Buote

    2000-04-01

    The inhomogeneous cooling flow scenario predicts the existence of large quantities of gas in massive elliptical galaxies, groups, and clusters that have cooled and dropped out of the flow. Using spatially resolved, deprojected X-ray spectra from the ROSAT PSPC, we have detected strong absorption over energies approximately 0.4-0.8 keV intrinsic to the central approximately 1&arcmin; of the galaxy NGC 1399, the group NGC 5044, and the cluster A1795. These systems have among the largest nearby cooling flows in their respective classes and low Galactic columns. Since no excess absorption is indicated for energies below approximately 0.4 keV, the most reasonable model for the absorber is warm, collisionally ionized gas with T=105-106 K in which ionized states of oxygen provide most of the absorption. Attributing the absorption only to ionized gas reconciles the large columns of cold H and He inferred from Einstein and ASCA with the lack of such columns inferred from ROSAT and also is consistent with the negligible atomic and molecular H inferred from H i and CO observations of cooling flows. The prediction of warm ionized gas as the product of mass dropout in these and other cooling flows can be verified by Chandra and X-Ray Multimirror Mission.

  5. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...

  6. Clustering of absorption line systems

    CERN Document Server

    Petitjean, P

    1996-01-01

    Absorption line systems are luminosity unbiased tracers of the spatial distribution of baryons over most of the history of the Universe. I review the importance of studying the clustering properties of the absorbers and the impact of VLT in this subject. The primary aim of the project is to track the evolution of the structures of the Universe back in time.

  7. Electromodulated absorption in smoky quartz

    NARCIS (Netherlands)

    Brom, W.E. van den; Volger, J.

    1974-01-01

    The optical absorption coefficient of “smoky” quartz (containing aluminium) can be modulated by applying an electric field. The effect saturates at high fields and low temperatures and reaches a maximum at 535 nm. The results are discussed in terms of a model consisting of a colour centre, dipolar i

  8. Absorptive capacity and smart companies

    Directory of Open Access Journals (Sweden)

    Patricia Moro González

    2014-12-01

    Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

  9. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-05-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from –0.79 to –0.53 W m−2 (33% and all-sky from –0.47 to –0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  10. Light as stress factor to plant roots - case of root halotropism.

    Science.gov (United States)

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives.

  11. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  12. Fate of HERS during Tooth Root Development

    OpenAIRE

    HUANG, XIAOFENG; BRINGAS, PABLO; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS c...

  13. Penis-root perception of Koro patients.

    Science.gov (United States)

    Chowdhury, A N

    1991-07-01

    Koro is an acute anxiety reaction in which the perception of decreased penis length because of intra-abdominal traction is the main feature. This study attempts to explore the penis-root perception of the Koro patients by a graphomotor projective test--the Draw-a-penis Test (DAPT). This controlled DAPT investigation shows that Koro patients perceived the penis as a detached organ with root-boundary definiteness as evidenced from their close penis-root perception. They also displayed reduced volumetric perception of penis-root than the normal subjects. These perceptual deviations in penis-root image are discussed in relation to their Koro vulnerability.

  14. On the use of antibiotics to reduce rhizoplane microbial populations in root physiology and ecology investigations

    Science.gov (United States)

    Smart, D. R.; Ferro, A.; Ritchie, K.; Bugbee, B. G.

    1995-01-01

    No straightforward method exists for separating the proportion of ion exchange and respiration due to rhizoplane microbial organisms from that of root ion exchange and respiration. We examined several antibiotics that might be used for the temporary elimination of rhizoplane bacteria from hydroponically grown wheat roots (Triticum aestivum cv. Veery 10). Each antibiotic was tested for herbicidal activity and plate counts were used to enumerate bacteria and evaluate antibiotic kinetics. Only lactam antibiotics (penicillins and cephalosporins) did not reduce wheat growth rates. Aminoglycosides, the pyrimidine trimethoprim, colistin and rifampicin reduced growth rates substantially. Antibiotics acted slowly, with maximum reductions in rhizoplane bacteria occurring after more than 48 h of exposure. Combinations of nonphytotoxic antibiotics reduced platable rhizoplane bacteria by as much as 98%; however, this was generally a reduction from about 10(9) to 10(6) colony forming units per gram of dry root mass, so that many viable bacteria remained on root surfaces. We present evidence which suggests that insufficient bacterial biomass exists on root surfaces of nonstressed plants grown under well-aerated conditions to quantitatively interfere with root nitrogen absorption measurements.

  15. Optimal root arrangement of cereal crops

    Science.gov (United States)

    Jung, Yeonsu; Park, Keunhwan; Kim, Ho-Young

    2015-11-01

    The plant root absorbs water from the soil and supplies it to the rest part of the plant. It consists of a number of root fibers, through whose surfaces water uptake occurs. There is an intriguing observation that for most of cereal crops such as maize and wheat, the volume density of root in the soil declines exponentially as a function of depth. To understand this empirical finding, we construct a theoretical model of root water uptake, where mass transfer into root surface is modeled just as heat flux around a fin. Agreement between the theoretically predicted optimal root distribution in vertical direction and biological data supports the hypothesis that the plant root has evolved to achieve the optimal water uptake in competition with neighbors. This study has practical implication in the agricultural industry as well as optimal design of water transport networks in both micro- and macroscales. Department of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.

  16. Effects of fine root length density and root biomass on soil preferential flow in forest ecosystems

    Directory of Open Access Journals (Sweden)

    Yinghu Zhang

    2015-04-01

    Full Text Available Aim of study: The study was conducted to characterize the impacts of plant roots systems (e.g., root length density and root biomass on soil preferential flow in forest ecosystems. Area of study: The study was carried out in Jiufeng National Forest Park, Beijing, China. Material and methods: The flow patterns were measured by field dye tracing experiments. Different species (Sophora japonica Linn,Platycladus orientalis Franco, Quercus dentata Thunbwere quantified in two replicates, and 12 soil depth were applied. Plant roots were sampled in the sieving methods. Root length density and root biomass were measured by WinRHIZO. Dye coverage was implied in the image analysis, and maximum depth of dye infiltration by direct measurement. Main results: Root length density and root biomass decreased with the increasing distance from soil surface, and root length density was 81.6% higher in preferential pathways than in soil matrix, and 66.7% for root biomass with respect to all experimental plots. Plant roots were densely distributed in the upper soil layers. Dye coverage was almost 100% in the upper 5-10 cm, but then decreased rapidly with soil depth. Root length density and root biomass were different from species: Platycladus orientalis Franco > Quercus dentata Thunb > Sophora japonica Linn. Research highlights: The results indicated that fine roots systems had strong effects on soil preferential flow, particularly root channels enhancing nutrition transport across soil profiles in forest dynamics.

  17. Root cap removal increases root penetration resistance in maize (Zea mays L).

    Science.gov (United States)

    Iijima, Morio; Higuchi, Toshifumi; Barlow, Peter W; Bengough, A Glyn

    2003-09-01

    The root cap assists the passage of the root through soil by means of its slimy mucilage secretion and by the sloughing of its outer cells. The root penetration resistance of decapped primary roots of maize (Zea mays L. cv. Mephisto) was compared with that of intact roots in loose (dry bulk density 1.0 g cm-3; penetration resistance 0.06 MPa) and compact soil (1.4 g cm-3; penetration resistance 1.0 MPa), to evaluate the contribution of the cap to decreasing the impedance to root growth. Root elongation rate and diameter were the same for decapped and intact roots when the plants were grown in loose soil. In compacted soil, however, the elongation rate of decapped roots was only about half that of intact roots, whilst the diameter was 30% larger. Root penetration resistances of intact and decapped seminal axis were 0.31 and 0.52 MPa, respectively, when the roots were grown in compacted soil. These results indicated that the presence of a root cap alleviates much of the mechanical impedance to root penetration, and enables roots to grow faster in compacted soils.

  18. Hydraulic responses of whole vines and individual roots of kiwifruit (Actinidia chinensis) following root severance.

    Science.gov (United States)

    Black, Marykate Z; Patterson, Kevin J; Minchin, Peter E H; Gould, Kevin S; Clearwater, Michael J

    2011-05-01

    Whole vine (K(plant)) and individual root (K(root)) hydraulic conductances were measured in kiwifruit (Actinidia chinensis Planch. var. chinensis 'Hort16A') vines to observe hydraulic responses following partial root system excision. Heat dissipation and compensation heat pulse techniques were used to measure sap flow in trunks and individual roots, respectively. Sap flux and measurements of xylem pressure potential (Ψ) were used to calculate K(plant) and K(root) in vines with zero and ∼80% of roots severed. Whole vine transpiration (E), Ψ and K(plant) were significantly reduced within 24 h of root pruning, and did not recover within 6 weeks. Sap flux in intact roots increased within 24 h of root pruning, driven by an increase in the pressure gradient between the soil and canopy and without any change in root hydraulic conductance. Photosynthesis (A) and stomatal conductance (g(s)) were reduced, without significant effects on leaf internal CO(2) concentration (c(i)). Shoot growth rates were maintained; fruit growth and dry matter content were increased following pruning. The woody roots of kiwifruit did not demonstrate a rapid dynamic response to root system damage as has been observed previously in monocot seedlings. Increased sap flux in intact roots with no change in K(root) and only a moderate decline in shoot A suggests that under normal growing conditions root hydraulic conductance greatly exceeds requirements for adequate shoot hydration.

  19. Sound absorption property of openpore aluminum foams

    Directory of Open Access Journals (Sweden)

    WANG Fang

    2007-02-01

    Full Text Available This paper presents a study on sound absorption property of aluminum foam by evaluating its sound absorption coefficients using standing wave tube method. Experimental results showed that the average values of sound absorption coefficients (over the test frequency range are all above 0.4, which indicate very good sound absorption property of the aluminum foams. The sound absorption coefficient is affected by frequency and pore structure, and reaches its maximum value at around 1 000 Hz. With the increase of porosity and decrease of cell diameter, the sound absorption coefficient values increase.

  20. Theory of graphene saturable absorption

    CERN Document Server

    Marini, A; de Abajo, F J Garcia

    2016-01-01

    Saturable absorption is a non-perturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a non-perturbative single-particle approach, describing conduction-electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics non-perturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. The results are in excellent agreement with atomistic quantum-mechanical simulations including high...

  1. Ectopic Expression of a Phytase Gene from Medicago truncatula Barrel Medic Enhances Phosphorus Absorption in Plants

    Institute of Scientific and Technical Information of China (English)

    Kai Xiao; Jian-Heng Zhang; Maria Harrison; Zeng-Yu Wang

    2006-01-01

    In the present study, the phosphorus-absorption capacity of transgenic Arabidopsis plants ectopically expressing a novel phytase gene from Medicago truncatula Barrel Medic was evaluated. A full-length cDNA encoding an extracellular form of phytase was isolated from the model legume M. truncatula. The phytase gene (MtPHY1) has an open reading frame of 1 632 bp predicted to encode 543 amino acids, including an Nterminal signal peptide of 27 amino acids. The genomic sequence of the MtPHY1 gene is 5 151 bp, containing seven exons interrupted by six introns. Under high-Pi (2 mmol/L) growth conditions, higher levels of MtPHY1transcripts accumulated in the leaf and stem than in the root. The transcript level was reduced in the stem and increased in the root, with no obvious changes in the hybridization signal detected in the leaf under lowPi (10 μmol/L) conditions. Chimeric transgenes were constructed by placing MtPHY1 under the control of the constitutive CaMV35S promoter and the root-specific MtPT1 promoter. Phytase activities in root apoplast of transgenic Arabidopsis were 12.3- to 16.2-fold of that in control plants. The phytase expressed was secreted into the rhizosphere, as demonstrated by HPLC analysis of phytate degradation by root exudates. Ectopic expression of MtPHY1 in Arabidopsis, leading to significant improvement in organic phosphorus absorption and plant growth, indicated that MtPHY1 has great potential for improving plant phosphorus absorption and phytoremediation.

  2. Geometrical interpretation of optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L. [Departamento de Optica, Facultad de Fisica, Universidad Complutense, E-28040 Madrid (Spain); Montesinos-Amilibia, J. M. [Departamento de Geometria y Topologia, Facultad de Matematicas, Universidad Complutense, E-28040 Madrid (Spain)

    2011-08-15

    We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.

  3. Photodetector with enhanced light absorption

    Science.gov (United States)

    Kane, James

    1985-01-01

    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  4. [XPS analysis of tea plant leaf and root surface].

    Science.gov (United States)

    Fang, Jiang-yu; Wan, Xiao-chun

    2008-09-01

    , verifying more active chemical property on the root surface and more water and solute molecules passing. Again the protein content was in the order of root, abaxial and adaxial, indicating the same order of the wetness degree. Higher binding energy of Al than 73. 50 eV showed oxidized aluminum in tea plant surface, which might enhance the absorption, and more oxidized aluminum in the root meants that it has more powerful absorbability.

  5. Practical absorption limits of MPP absorber

    Institute of Scientific and Technical Information of China (English)

    MAA Dah-You

    2006-01-01

    The construction and properties of microperforated panel (MPP) absorber are discussed. The absorption limit of the absorber had been shown that low values of the perforate constant k = d(f/10)1/2 and the orifice diameter d (in mm) are essential for MPP to have high absorption in wide frequency band. To find the exact limits, take 1 for k as a start, because both specific resistance and high absorption require k around one. And the orifice diameter d is chosen as 0.1 mm, so that the peak absorption coefficient (resonance absorption) is at 1000 Hz,and high sound frequency may be in the absorption region. Is it possible for a single layer of such an MPP to cover the whole absorption region required in practice? The half-absorption limit is not a good criterion, because low absorption comes in also in some cases. The 0.5 absorption coefficient limit is suggested for practical region, as a standard for comparison. Absorption curves were drawn for different load resistances, of absorption coefficients versus frequency.Ordinary MPP absorber absorbs in slightly over two octaves, and the new absorber with r = 1 (specific resistance equal to the characteristic impedance in air)is slightly better than these, 2.5 octaves. The new absorbers with r > 1, are much better than these, and some satisfies high absorption in broad frequency range. Realization of these will mean great progress of MPP absorbers.

  6. QED-driven laser absorption

    CERN Document Server

    Levy, M C; Ratan, N; Sadler, J; Ridgers, C P; Kasim, M; Ceurvorst, L; Holloway, J; Baring, M G; Bell, A R; Glenzer, S H; Gregori, G; Ilderton, A; Marklund, M; Tabak, M; Wilks, S C; Norreys, P A

    2016-01-01

    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser illuminates optically-thick matter. It underpins important petawatt-scale applications today, e.g., medical-quality proton beam production. However, development of ultra-high-field applications has been hindered since no study so far has described absorption throughout the entire transition from the classical to the quantum electrodynamical (QED) regime of plasma physics. Here we present a model of absorption that holds over an unprecedented six orders-of-magnitude in optical intensity and lays the groundwork for QED applications of laser-driven particle beams. We demonstrate 58% efficient \\gamma-ray production at $1.8\\times 10^{25}~\\mathrm{W~ cm^{-2}}$ and the creation of an anti-matter source achieving $4\\times 10^{24}\\ \\mathrm{positrons}\\ \\mathrm{cm^{-3}}$, $10^{6}~\\times$ denser than of any known photonic scheme. These results will find applications in scaled laboratory probes of bla...

  7. Effects of Local Nitrogen Supply on Water Uptake of Bean Plants in a Split Root System

    Institute of Scientific and Technical Information of China (English)

    Shiwei Guo; Qirong Shen; Holger Brueck

    2007-01-01

    To study the effects of local nitrogen supply on water and nutrient absorption, French bean (Phaseolus vulgaris L.)plants were grown in a split root system. Five treatments supplied with different nitrogen forms were compared:homogeneous nitrate (NN) and homogenous ammonium (AA) supply, spatially separated supply of nitrate and ammonium (NA), half of the root system supplied with N-free nutrient solution, the other half with either nitrate (NO) or ammonium (AO). The results showed that 10 d after onset of treatments, root dry matter (DM) in the nitratesupplied vessels treated with NA was more than two times higher than that in the ammonium-supplied vessels.Water uptake from the nitrate-supplied vessels treated with NA was 281% higher than under ammonium supply. In treatments NO and AO, the local supply of N resulted in clearly higher root DM, and water uptake from the nitratesupplied vessels was 82% higher than in the -N vessels. However, in AO plants, water uptake from the -N nutrient solution was 129% higher than from the ammonium-supplied vessels. This indicates a compensatory effect, which resulted in almost identical rates of total water uptake of treatments AA and AO, which had comparable shoot DM and leaf area. Ammonium supply reduced potassium and magnesium absorption. Water uptake was positively correlated with N, Mg and K uptake.

  8. Inhibition of Cariogenic Plaque Formation on Root Surface with Polydopamine-Induced-Polyethylene Glycol Coating

    Directory of Open Access Journals (Sweden)

    May Lei Mei

    2016-05-01

    Full Text Available Root caries prevention has been a challenge for clinicians due to its special anatomical location, which favors the accumulation of dental plaque. Researchers are looking for anti-biofouling material to inhibit bacterial growth on exposed root surfaces. This study aimed to develop polydopamine-induced-polyethylene glycol (PEG and to study its anti-biofouling effect against a multi-species cariogenic biofilm on the root dentine surface. Hydroxyapatite disks and human dentine blocks were divided into four groups for experiments. They received polydopamine-induced-PEG, PEG, polydopamine, or water application. Contact angle, quartz crystal microbalance, and Fourier transform infrared spectroscopy were used to study the wetting property, surface affinity, and an infrared spectrum; the results indicated that PEG was induced by polydopamine onto a hydroxyapatite disk. Salivary mucin absorption on hydroxyapatite disks with polydopamine-induced-PEG was confirmed using spectrophotometry. The growth of a multi-species cariogenic biofilm on dentine blocks with polydopamine-induced-PEG was assessed and monitored by colony-forming units, confocal laser scanning microscopy, and scanning electron microscopy. The results showed that dentine with polydopamine-induced-PEG had fewer bacteria than other groups. In conclusion, a novel polydopamine-induced-PEG coating was developed. Its anti-biofouling effect inhibited salivary mucin absorption and cariogenic biofilm formation on dentine surface and thus may be used for the prevention of root dentine caries.

  9. Localization and speciation of Zn in mycorrhized roots by {mu}SXRF and{mu}EXAFS

    Energy Technology Data Exchange (ETDEWEB)

    Sarret, G.; Schroeder, W.H.; Marcus, Matthew A.; Geoffroy, N.; Manceau, Alain

    2004-09-23

    Mycorrizae are symbiotic associations between soil fungi and plant roots, which enhance mineral nutrition for the plant, and might play an important role in metals acquisition and accumulation. The processes allowing metal mobilization in the soil, absorption by the root and/or the fungus, transfer or bioaccumulation are still poorly understood. However, the properties of mycorrhizal fungi could be used for phytoremediation, a soft technique using plants for the clean-up of metal-polluted soils. In this work, mycorrhized roots of tomato plants grown in a Zn-contaminated soil were investigated. The distribution of metals and the speciation of Zn were studied on the micron scale using micro synchrotron-based X-ray fluorescence and micro X-ray absorption spectroscopy. Zn associated to the root was Zn malate and/or Zn citrate, and Zn associated to the fungus was Zn phyllosilicate. This study illustrates the great potential of X-ray microbeams for the study of biological samples containing various amounts of metals.

  10. Patterns in soil fertility and root herbivory interact to influence fine-root dynamics.

    Science.gov (United States)

    Stevens, Glen N; Jones, Robert H

    2006-03-01

    Fine-scale soil nutrient enrichment typically stimulates root growth, but it may also increase root herbivory, resulting in trade-offs for plant species and potentially influencing carbon cycling patterns. We used root ingrowth cores to investigate the effects of microsite fertility and root herbivory on root biomass in an aggrading upland forest in the coastal plain of South Carolina, USA. Treatments were randomly assigned to cores from a factorial combination of fertilizer and insecticide. Soil, soil fauna, and roots were removed from the cores at the end of the experiment (8-9 mo), and roots were separated at harvest into three diameter classes. Each diameter class responded differently to fertilizer and insecticide treatments. The finest roots (root biomass, were the only ones to respond significantly to both treatments, increasing when fertilizer and when insecticide were added (each P root-feeding insects have a strong influence on root standing crop with stronger herbivore impacts on finer roots and within more fertile microsites. Thus, increased vulnerability to root herbivory is a potentially significant cost of root foraging in nutrient-rich patches.

  11. Inhibition of auxin movement from the shoot into the root inhibits lateral root development in Arabidopsis

    Science.gov (United States)

    Reed, R. C.; Brady, S. R.; Muday, G. K.

    1998-01-01

    In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

  12. 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

  13. A statistical approach to root system classification.

    Science.gov (United States)

    Bodner, Gernot; Leitner, Daniel; Nakhforoosh, Alireza; Sobotik, Monika; Moder, Karl; Kaul, Hans-Peter

    2013-01-01

    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. The classification method presented is based on a data-defined statistical procedure without a priori decision on the classifiers. The study demonstrates that principal component based rooting types provide efficient and meaningful multi-trait classifiers. 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. Rooting types emerging from measured data, mainly distinguished by diameter/weight and density dominated types. 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 techniques are essential.

  14. Towards understanding tree root profiles: simulating hydrologically optimal strategies for root distribution

    Directory of Open Access Journals (Sweden)

    M. T. van Wijk

    2001-01-01

    Full Text Available In this modelling study differences in vertical root distributions measured in four contrasting forest locations in the Netherlands were investigated. Root distributions are seen as a reflection of the plant’s optimisation strategy, based on hydrological grounds. The 'optimal' root distribution is defined as the one that maximises the water uptake from the root zone over a period of ten years. The optimal root distributions of four forest locations with completely different soil physical characteristics are calculated using the soil hydrological model SWIF. Two different model configurations for root interactions were tested: the standard model configuration in which one single root profile was used (SWIF-NC, and a model configuration in which two root profiles compete for the same available water (SWIF-C. The root profiles were parameterised with genetic algorithms. The fitness of a certain root profile was defined as the amount of water uptake over a simulation period of ten years. The root profiles of SWIF-C were optimised using an evolutionary game. The results showed clear differences in optimal root distributions between the various sites and also between the two model configurations. Optimisation with SWIF-C resulted in root profiles that were easier to interpret in terms of feasible biological strategies. Preferential water uptake in wetter soil regions was an important factor for interpretation of the simulated root distributions. As the optimised root profiles still showed differences with measured profiles, this analysis is presented, not as the final solution for explaining differences in root profiles of vegetation but as a first step using an optimisation theory to increase understanding of the root profiles of trees. Keywords: forest hydrology, optimisation, roots

  15. Root canal treatment of bilateral three-rooted maxillary first premolars

    Directory of Open Access Journals (Sweden)

    Bhavana Gandhi

    2012-01-01

    Full Text Available In endodontics, several anatomic variations occur in teeth, both externally and in the internal root morphology, which play a very significant role in the diagnosis and treatment outcome. A thorough knowledge of the root canal anatomy, careful interpretation of the angled radiographs, proper endodontic access cavity preparation, and exploration of the root canal are the prerequisites for endodontic success. In a maxillary first premolar, it is rare to find extra roots and canals, and the aim of the present article is to report a case about the successful diagnosis and clinical management of bilateral three-rooted maxillary first premolars, with three independent root canals.

  16. Resonant Optical Absorption in Semiconductor Quantum Wells

    Institute of Scientific and Technical Information of China (English)

    YU Li-Yuan; CAO Jun-Cheng

    2004-01-01

    @@ We have calculated the intraband photon absorption coefficients of hot two-dimensional electrons interacting with polar-optical phonon modes in quantum wells. The dependence of the photon absorption coefficients on the photon wavelength λ is obtained both by using the quantum mechanical theory and by the balance-equation theory. It is found that the photon absorption spectrum displays a local resonant maximum, corresponding to LO energy, and the absorption peak vanishes with increasing the electronic temperature.

  17. Evolution of absorption machines; Evolution des machines a absorption

    Energy Technology Data Exchange (ETDEWEB)

    Soide, I.; Klemsdal, E. [Gaz de France (GDF), 75 - Paris (France); Le Goff, P.; Hornut, J.M. [LSGC-ENSIC, 54 - Nancy (France)

    1997-12-31

    Most of todays absorption air-conditioning machineries use the lithium bromide-water pair. The most performing can operate at a 150-160 deg. C, the temperature being limited by the corrosion resistance of metals with respect to LiBr solutions. Also, there is a revival of interest for water-ammonia systems. These systems require the use of a rectification column which reduces the coefficient of performance. Higher thermal performances are reached with hydrocarbon pairs and ternary mixtures (water-methanol-LiBr etc..). This paper presents different schemes of refrigerating heat pumps based on these different systems. (J.S.)

  18. Winter Wheat Root Growth and Nitrogen Relations

    DEFF Research Database (Denmark)

    Rasmussen, Irene Skovby

    Root growth is an essential parameter regarding nitrogen (N) uptake efficiency, as more and deeper roots may improve the uptake from deeper soil layers and reduce nitrate leaching losses. During this PhD project, it was studied how different agronomic practices influence root growth and N relations...... in winter wheat (Triticum aestivum L). Field experiments on the effect of sowing date, N fertilization and cultivars were conducted on a sandy loam soil in Taastrup, Denmark. The root studies were conducted by means of the minirhizotron method. Also, a field experiment on the effect of defoliation and N...... fertilization was conducted in Canberra, Australia. Here the root studies were done by means of the core-break method and root washing....

  19. Systems approaches to study root architecture dynamics

    Directory of Open Access Journals (Sweden)

    Candela eCuesta

    2013-12-01

    Full Text Available The plant root system is essential for providing anchorage to the soil, supplying minerals and water, and synthesizing metabolites. It is a dynamic organ modulated by external cues such as environmental signals, water and nutrients availability, salinity and others. Lateral roots are initiated from the primary root post-embryonically, after which they progress through discrete developmental stages which can be independently controlled, providing a high level of plasticity during root system formation.Within this review, main contributions are presented, from the classical forward genetic screens to the more recent high-throughput approaches, combined with computer model predictions, dissecting how lateral roots and thereby root system architecture is established and developed.

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

    Directory of Open Access Journals (Sweden)

    P.S. Kruger

    2012-01-01

    Full Text Available

    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 closely linked to the history of probability and statistics and hence games of chance, gambling and divinity. Therefore, the life and times, contributions and personalities of some of the heroes and villains, champions and sad cases of the stochastic world, will be briefly discussed in a somewhat light-hearted, but not necessarily flippant, manner.

    AFRIKAANSE OPSOMMING: Die “wortel en tak” van Bedryfsingenieurswese is sekerlik van groot omvang, van diverse aard en diep gesetel. Verskeie historiese “helde” het betekenisvolle bydraes gemaak tot die ontwikkeling van die Bedryfsingenieurswesevakgebied. Ter wille van betoogvoering sal in hierdie artikel aanvaar word dat Bedryfsingenieurswese uit minstens twee identifiseerbare sub-vakgebiede bestaan naamlik : Die Determinisme en die Stogasme. ’n Poging word aangewend om die vroeë geskiedenis van die stogasme na te speur wat op sy beurt aaneengesnoer is met die geskiedenis van die waarskynlikheidsleer en statistiek en dus toevalspelle, dobbelary en wiggelary. Die lewenswyse, tydsgewrig, bydraes en persoonlikheidseienskappe van ’n aantal helde en skurke, kampioene en prulle van die stogastiese wêreld word kortliks bespreek, op ’n ietwat lighartige maar nie noodwendig ligsinnige wyse.

  1. Root phenology in a changing climate.

    Science.gov (United States)

    Radville, Laura; McCormack, M Luke; Post, Eric; Eissenstat, David M

    2016-06-01

    Plant phenology is one of the strongest indicators of ecological responses to climate change, and altered phenology can have pronounced effects on net primary production, species composition in local communities, greenhouse gas fluxes, and ecosystem processes. Although many studies have shown that aboveground plant phenology advances with warmer temperatures, demonstration of a comparable association for belowground phenology has been lacking because the factors that influence root phenology are poorly understood. Because roots can constitute a large fraction of plant biomass, and root phenology may not respond to warming in the same way as shoots, this represents an important knowledge gap in our understanding of how climate change will influence phenology and plant performance. We review studies of root phenology and provide suggestions to direct future research. Only 29% of examined studies approached root phenology quantitatively, strongly limiting interpretation of results across studies. Therefore, we suggest that researchers emphasize quantitative analyses in future phenological studies. We suggest that root initiation, peak growth, and root cessation may be under different controls. Root initiation and cessation may be more constrained by soil temperature and the timing of carbon availability, whereas the timing of peak root growth may represent trade-offs among competing plant sinks. Roots probably do not experience winter dormancy in the same way as shoots: 89% of the studies that examined winter phenology found evidence of growth during winter months. More research is needed to observe root phenology, and future studies should be careful to capture winter and early season phenology. This should be done quantitatively, with direct observations of root growth utilizing rhizotrons or minirhizotrons.

  2. Rooting of carnation cuttings: The auxin signal

    OpenAIRE

    Acosta, Manuel; Oliveros-Valenzuela, M Rocío; Nicolás, Carlos; Sánchez-Bravo, José

    2009-01-01

    The rooting of stem cuttings is a common vegetative propagation practice in many ornamental species. Among other signals, auxin polarly transported through the stem plays a key role in the formation and growth of adventitious roots. Unlike in other plant species, auxin from mature leaves plays a decisive role in the rooting of carnation (Dianthus caryophyllus. L) cuttings. The gene DcAUX1, which codifies an auxin influx carrier involved in polar auxin transport, has now been cloned and charac...

  3. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone.

    Science.gov (United States)

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia Jun; Eng, Christopher; Liu, Chang Jun; Tappero, Ryan

    2016-07-01

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  4. Designing new interfaces for ROOT data processing

    CERN Document Server

    Vuorinen, Kalle Elmer

    2016-01-01

    ROOT is a C++ framework for data analysis provided with a Python interface (PyRoot). ROOT is used in every Large Hadron Collider experiment. This project presents a way of reading ROOT TTree by using a new class called DataFrame, which allows the usage of cache and functional chains. Reading TTrees in Python has been quite slow compared to the C++ way of doing it and for this reason we also bring the possibility to read them with just-in-time (JIT) compiled C++ code, using another new Python class called TreeReader.

  5. Mandibular second premolar with four roots

    Directory of Open Access Journals (Sweden)

    Sefika Nur Akyuz

    2012-01-01

    Full Text Available Detection of normal and abnormal variation in tooth anatomy is essential for clinical success. It is generally well known that the mandibular second premolar teeth have a single root and canal. However, the mandibular second premolar teeth have sometimes more than one root and root canal. The endodontic treatment of a mandibular second premolar with four roots which separated at different levels along the middle third of the root is presented in this case report. Preoperative radiographs appeared radiolucency and different root anatomy in the region of the mandibular second premolar. The root canals were prepared using Mtwo rotary system (VDW, Munich, Germany and obturated laterally condensed gutta percha and AH plus (Dentsply De Trey, Konstanz, Germany. After the completion of root canal treatment, the tooth was restored with a posterior composite filling material. On follow-up, the tooth was clinically and radiographically asymptomatic for two years. Clinicians should be aware of the importance of careful clinical and radiographic examination of mandibular premolars during the endodontic treatment. Radiographs exposed at two different horizontal angles and their careful interpretation facilitates the search of additional root canals.

  6. Power Efficient Division and Square Root Unit

    DEFF Research Database (Denmark)

    Liu, Wei; Nannarelli, Alberto

    2012-01-01

    shows that division and square root units based on the digit-recurrence algorithm offer the best tradeoff delay-area-power. Moreover, the two operations can be combined in a single unit. Here, we present a radix-16 combined division and square root unit obtained by overlapping two radix-4 stages......Although division and square root are not frequent operations, most processors implement them in hardware to not compromise the overall performance. Two classes of algorithms implement division or square root: digit-recurrence and multiplicative (e.g., Newton-Raphson) algorithms. Previous work...

  7. Mineral nutrition and adventitious rooting in microcuttings of Eucalyptus globulus.

    Science.gov (United States)

    Schwambach, Joséli; Fadanelli, Cristina; Fett-Neto, Arthur G

    2005-04-01

    We characterized the adventitious rooting response of Eucalyptus globulus Labill. to various concentrations of calcium, nitrogen, phosphorus, iron, manganese, zinc, boron and copper. The parameters analyzed were percent rooting, root number, root length and mean rooting time. Root number and root length were significantly affected by mineral nutrition, whereas mean rooting time and rooting percentage seemed to be closely related to auxin availability. Root number was affected by calcium, nitrogen source and zinc, whereas root length was influenced by concentrations of phosphorus, iron and manganese, and by nitrogen source. Based on these results, we evaluated various combinations of several concentrations of these minerals in each rooting phase. Cuttings that were rooted in an optimized mineral nutrient medium and acclimatized to ex-vitro conditions for two months showed significantly higher survival after transplanting and drought stress than cuttings rooted in basal medium and treated in the same way.

  8. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  9. ROOT HYDRAULIC CONDUCTIVITY AND PHOTOSYNTHETIC CAPACITY OF EUCALYPT CLONAL CUTTINGS WITH ROOT MALFORMATION INDUCTIONS

    Directory of Open Access Journals (Sweden)

    Fábio Afonso Mazzei Moura de Assis Figueiredo

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814566The gain reduction of wood biomass in trees has been assigned to root deformations even in the nursery phase. The objective of this work was the evaluation of the root system hydraulic conductivity, gas exchanges and photochemical efficiency of eucalypt clonal cuttings with and without root deformation inductions. The treatments were: 1 operational cuttings without root malformation inductions (grown according to the used methodology of Fibria Cellulose S.A.; 2 root deformation inductions. These inductions did not promote decrease in the root volume. However, the deformations brought reduction of the root system hydraulic conductivity. Lower photosynthetic rates were also observed along the day in the cuttings in the root deformed cuttings. This decreasing rate is connected to stomatal and non stomatal factors.

  10. 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

  11. Anatomical evaluation of the root canal diameter and root thickness on the apical third of mesial roots of molars.

    Science.gov (United States)

    Martos, Josué; Tatsch, Gustavo Henrique; Tatsch, Augusto César; Silveira, Luiz Fernando Machado; Ferrer-Luque, Carmen María

    2011-09-01

    The purpose was to determine the diameter of the main root canal and wall thickness in the apical dentin in mesial roots of maxillary and mandibular molars. Forty mesiobuccal and mesial root specimens were sectioned horizontally at 1, 2 and 3 mm from the apex, and measured at each top surface by using optical microscopy to an accuracy of ×20 magnification. The anatomical parameters were established as the following points of reference: AB, two points connected by a line from the outer edge of the mesial wall to the outer edge of the distal one through the center of the root canal to measure the thickness of the root and mesiodistal diameter of the root canal (CD). A second line (EF) was designed to evaluate the diameter of the root canal in the buccolingual direction. All data were summarized, and values were assessed statistically by ANOVA and Bonferroni multiple comparisons. The buccolingual (BL) root canal diameters at 1, 2 and 3 mm in the mandibular and maxillary molars were greater than in the mesiodistal (MD), showing statistically significant differences (p maxillary molars were statistically significant (p maxillary molars was 1.741 mm. The BL diameters in maxillary and mandibular molars were higher than the MD diameter. The thickness (MD) of maxillary and mandibular molars decreased as a function of apical proximity.

  12. Piriformospora indica root colonization triggers local and systemic root responses and inhibits secondary colonization of distal roots.

    Directory of Open Access Journals (Sweden)

    Lorenzo Pedrotti

    Full Text Available Piriformosporaindica is a basidiomycete fungus colonizing roots of a wide range of higher plants, including crop plants and the model plant Arabidopsis thaliana. Previous studies have shown that P. indica improves growth, and enhances systemic pathogen resistance in leaves of host plants. To investigate systemic effects within the root system, we established a hydroponic split-root cultivation system for Arabidopsis. Using quantitative real-time PCR, we show that initial P. indica colonization triggers a local, transient response of several defense-related transcripts, of which some were also induced in shoots and in distal, non-colonized roots of the same plant. Systemic effects on distal roots included the inhibition of secondary P. indica colonization. Faster and stronger induction of defense-related transcripts during secondary inoculation revealed that a P. indica pretreatment triggers root-wide priming of defense responses, which could cause the observed reduction of secondary colonization levels. Secondary P. indica colonization also induced defense responses in distant, already colonized parts of the root. Endophytic fungi therefore trigger a spatially specific response in directly colonized and in systemic root tissues of host plants.

  13. GiA Roots: software for the high throughput analysis of plant root system architecture

    OpenAIRE

    Galkovskyi Taras; Mileyko Yuriy; Bucksch Alexander; Moore Brad; Symonova Olga; Price Charles A; Topp Christopher N; Iyer-Pascuzzi Anjali S; Zurek Paul R; Fang Suqin; Harer John; Benfey Philip N; Weitz Joshua S

    2012-01-01

    Abstract Background Characterizing root system architecture (RSA) is essential to understanding the development and function of vascular plants. Identifying RSA-associated genes also represents an underexplored opportunity for crop improvement. Software tools are needed to accelerate the pace at which quantitative traits of RSA are estimated from images of root networks. Results We have developed GiA Roots (General Image Analysis of Roots), a semi-automated software tool designed specifically...

  14. Five-Photon Absorption and Selective Enhancement of Multiphoton Absorption Processes.

    Science.gov (United States)

    Friese, Daniel H; Bast, Radovan; Ruud, Kenneth

    2015-05-20

    We study one-, two-, three-, four-, and five-photon absorption of three centrosymmetric molecules using density functional theory. These calculations are the first ab initio calculations of five-photon absorption. Even- and odd-order absorption processes show different trends in the absorption cross sections. The behavior of all even- and odd-photon absorption properties shows a semiquantitative similarity, which can be explained using few-state models. This analysis shows that odd-photon absorption processes are largely determined by the one-photon absorption strength, whereas all even-photon absorption strengths are largely dominated by the two-photon absorption strength, in both cases modulated by powers of the polarizability of the final excited state. We demonstrate how to selectively enhance a specific multiphoton absorption process.

  15. Root selection methods in flood analysis

    Directory of Open Access Journals (Sweden)

    B. Parmentier

    2003-01-01

    Full Text Available In the 1970s, de Laine developed a root-matching procedure for estimating unit hydrograph ordinates from estimates of the fast component of the total runoff from multiple storms. Later, Turner produced a root selection method which required only data from one storm event and was based on recognising a pattern typical of unit hydrograph roots. Both methods required direct runoff data, i.e. prior separation of the slow response. This paper introduces a further refinement, called root separation, which allows the estimation of both the unit hydrograph ordinates and the effective precipitation from the full discharge hydrograph. It is based on recognising and separating the quicker component of the response from the much slower components due to interflow and/or baseflow. The method analyses the z-transform roots of carefully selected segments of the full hydrograph. The root patterns of these separate segments tend to be dominated by either the fast response or the slow response. This paper shows how their respective time-scales can be distinguished with an accuracy sufficient for practical purposes. As an illustration, theoretical equations are derived for a conceptual rainfall-runoff system with the input split between fast and slow reservoirs in parallel. These are solved analytically to identify the reservoir constants and the input splitting parameter. The proposed method, called 'root separation', avoids the subjective selection of rainfall roots in the Turner method as well as the subjective matching of roots in the original de Laine method. Keywords: unit hydrograph,identification methods, z-transform, polynomial roots, root separation, fast andslow response, Nash cascade

  16. Malformations of the tooth root in humans

    Directory of Open Access Journals (Sweden)

    Hans Ulrich eLuder

    2015-10-01

    Full Text Available The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on

  17. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  18. 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.

  19. QED-driven laser absorption

    Science.gov (United States)

    Levy, Matthew; Blackburn, T.; Ratan, N.; Sadler, J.; Ridgers, C.; Kasim, M.; Ceurvorst, L.; Holloway, J.; Baring, M.; Bell, A.; Glenzer, S.; Gregori, G.; Ilderton, A.; Marklund, M.; Tabak, M.; Wilks, S.; Norreys, P.

    2016-10-01

    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser (I >1018 W cm-2 where I is intensity at 1 μm wavelength) illuminates optically-thick matter. It underpins important applications of petawatt laser systems today, e.g., in isochoric heating of materials. Next-generation lasers such as ELI are anticipated to produce quantum electrodynamical (QED) bursts of γ-rays and anti-matter via the multiphoton Breit-Wheeler process which could enable scaled laboratory probes, e.g., of black hole winds. Here, applying strong-field QED to advances in plasma kinematic theory, we present a model elucidating absorption limited only by an avalanche of self-created electron-positron pairs at ultra-high-field. The model, confirmed by multidimensional QED-PIC simulations, works over six orders of magnitude in optical intensity and reveals this cascade is initiated at 1.8 x 1025 W cm-2 using a realistic linearly-polarized laser pulse. Here the laser couples its energy into highly-collimated electrons, ions, γ-rays, and positrons at 12%, 6%, 58% and 13% efficiency, respectively. We remark on attributes of the QED plasma state and possible applications.

  20. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  1. Iron Absorption in Drosophila melanogaster

    Science.gov (United States)

    Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

    2013-01-01

    The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration. PMID:23686013

  2. Iron Absorption in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Fanis Missirlis

    2013-05-01

    Full Text Available The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import, the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export and the role of ferritin in the process of iron acquisition (iron storage. We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.

  3. Morphoanatomical responses induced by excess iron in roots of two tolerant grass species.

    Science.gov (United States)

    de Araújo, Talita Oliveira; de Freitas-Silva, Larisse; Santana, Brenda Vila Nova; Kuki, Kacilda Naomi; Pereira, Eduardo Gusmão; Azevedo, Aristéa Alves; da Silva, Luzimar Campos

    2015-02-01

    We aimed to verify whether morphoanatomic alterations occur in response to excess iron, in roots of Setaria parviflora and Paspallum urvillei (Poaceae), and to localize the presence of the sites of iron accumulation. Plants were subjected to 0.009, 1, 2, 4, and 7 mM Fe-EDTA in nutrient solution. Both species presented iron contents in the roots above the critical toxicity level. The presence of iron plaque on roots of the two species was confirmed, and it may have reduced iron absorption by the plants. Roots from the two species showed typical visual symptoms of stress by excess iron: change in color and mucilaginous and flaccid appearance. Anatomical damage was observed in both species: aerenchyma disruption, alterations in endodermal cells, and irregular shape of both vessel and sieve tube elements. The metal was histolocalized in the cortex and in protoxylem and metaxylem cell walls in both species, which suggests a detoxification strategy for the excess iron. Phenolic compounds were not histolocalized in roots. Microscopic analyses were therefore effective in evaluating the real damage caused by excess iron.

  4. Assessment of the nonoperated root after apical surgery of the other root in mandibular molars

    DEFF Research Database (Denmark)

    Kraus, Riccardo D; von Arx, Thomas; Gfeller, David

    2015-01-01

    INTRODUCTION: If a surgical approach is chosen to treat a multirooted tooth affected by persistent periapical pathosis, usually only the affected roots are operated on. The present study assessed the periapical status of the nonoperated root 5 years after apical surgery of the other root in mandi...

  5. Changes of Root Length and Root-to-Crown Ratio after Apical Surgery

    DEFF Research Database (Denmark)

    von Arx, Thomas; Jensen, Simon S; Bornstein, Michael M

    2015-01-01

    INTRODUCTION: Apical surgery is an important treatment option for teeth with post-treatment periodontitis. Although apical surgery involves root-end resection, no morphometric data are yet available about root-end resection and its impact on the root-to-crown ratio (RCR). The present study assess...

  6. X-ray computed tomography uncovers root-root interactions: quantifying spatial relationships between interacting root systems in three dimensions

    Directory of Open Access Journals (Sweden)

    Alexander Martin Paya

    2015-04-01

    Full Text Available Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen and Picea mariana (black spruce seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for two months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals and paired seedlings (inter- or intra-specific, than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.

  7. [Construction of root library by SSH and preliminary analysis of genes responsible for phosphorus deficiency in maize].

    Science.gov (United States)

    Huang, Q; Gao, S B; Zhang, Z M; Lin, H J; Pan, G T; Yang, K C; Rong, T Z

    2010-12-01

    An elite maize inbred line with high tolerance to low phosphorus, 178, was studied for constructing root library and analyzing some genes closely related to phosphorus (P) deficiency using SSH and Semi-quantitative RT-PCR. As a result, 3648 preliminary clones were obtained for root library under stress of P deficiency. By DNA sequencing of 34 random clones, we obtained 23 unique EST sequences which are involved in functions of root cell structure, tolerance and defense, protein modification and composition, transcription regulation, metabolism, and other unknown aspects. Five representative genes were further analyzed for their expression models. The results suggested that the molecular mechanism to adapt P deficiency in maize, performed by multi-genes with different contributions, is similar to rice, Arabidopsis and soybean. The expression order of 5 low P tolerant genes in maize root was PAP, GCS, TOM, PDI and AIP. And it was considered preliminarily that physiological and biochemical changes were prior to morphologic changes in maize root and the essential tolerance to low P may be determined by extending absorption of P to wide soil range through adaption of root architecture and root secretions, which is the greatest difference between tolerant and sensitive maize varieties under low P stress.

  8. On König's root finding algorithms

    DEFF Research Database (Denmark)

    Buff, Xavier; Henriksen, Christian

    2003-01-01

    In this paper, we first recall the definition of a family of root-finding algorithms known as König's algorithms. We establish some local and some global properties of those algorithms. We give a characterization of rational maps which arise as König's methods of polynomials with simple roots. We...

  9. Layers of root nouns in Germanic

    DEFF Research Database (Denmark)

    Hansen, Bjarne Simmelkjær Sandgaard

    2015-01-01

    The root-noun declension became productive in early Germanic, containing (I) inherited root nouns, (IIa) original substrate or loan words, and transitions from other declensions in (IIb) Proto-Germanic and (III) North Germanic. As ablaut was abolished, the inherited type would display ablaut grad...

  10. A histochemical study of root nodule development.

    NARCIS (Netherlands)

    Wiel, van de C.C.M.

    1991-01-01

    In cooperation with soil bacteria of the genera Rhizobium , Bradyrhizobium or Azorhizobium , many members of the legume family are able to form specialized organs on their roots, called root nodules. The bacteria, wrapped up inside a plant membrane, are accomodated in large parenchymatic cells locat

  11. Graphing Powers and Roots of Complex Numbers.

    Science.gov (United States)

    Embse, Charles Vonder

    1993-01-01

    Using De Moivre's theorem and a parametric graphing utility, examines powers and roots of complex numbers and allows students to establish connections between the visual and numerical representations of complex numbers. Provides a program to numerically verify the roots of complex numbers. (MDH)

  12. Cytological and ultrastructural studies on root tissues

    Science.gov (United States)

    Slocum, R. D.; Gaynor, J. J.; Galston, A. W.

    1984-01-01

    The anatomy and fine structure of roots from oat and mung bean seedlings, grown under microgravity conditions for 8 days aboard the Space Shuttle, was examined and compared to that of roots from ground control plants grown under similar conditions. Roots from both sets of oat seedlings exhibited characteristic monocotyledonous tissue organization and normal ultrastructural features, except for cortex cell mitochondria, which exhibited a 'swollen' morphology. Various stages of cell division were observed in the meristematic tissues of oat roots. Ground control and flight-grown mung bean roots also showed normal tissue organization, but root cap cells in the flight-grown roots were collapsed and degraded in appearance, especially at the cap periphery. At the ultrastructural level, these cells exhibited a loss of organelle integrity and a highly-condensed cytoplasm. This latter observation perhaps suggests a differing tissue sensitivity for the two species to growth conditions employed in space flight. The basis for abnormal root cap cell development is not understood, but the loss of these putative gravity-sensing cells holds potential significance for long term plant growth orientation during space flight.

  13. Rapid phenotyping of alfalfa root system architecture

    Science.gov (United States)

    Root system architecture (RSA) influences the capacity of an alfalfa plant for symbiotic nitrogen fixation, nutrient uptake and water use efficiency, resistance to frost heaving, winterhardiness, and some pest and pathogen resistance. However, we currently lack a basic understanding of root system d...

  14. Salt stress signals shape the plant root

    NARCIS (Netherlands)

    C.S. Galvan-Ampudia; C. Testerink

    2011-01-01

    Plants use different strategies to deal with high soil salinity. One strategy is activation of pathways that allow the plant to export or compartmentalise salt. Relying on their phenotypic plasticity, plants can also adjust their root system architecture (RSA) and the direction of root growth to avo

  15. Tissue engineering in endodontics: root canal revascularization.

    Science.gov (United States)

    Palit Madhu Chanda; Hegde, K Sundeep; Bhat, Sham S; Sargod, Sharan S; Mantha, Somasundar; Chattopadhyay, Sayan

    2014-01-01

    Root canal revascularization attempts to make necrotic tooth alive by the use of certain simple clinical protocols. Earlier apexification was the treatment of choice for treating and preserving immature permanent teeth that have lost pulp vitality. This procedure promoted the formation of apical barrier to seal the root canal of immature teeth and nonvital filling materials contained within root canal space. However with the success of root canal revascularization to regenerate the pulp dentin complex of necrotic immature tooth has made us to rethink if apexification is at the beginning of its end. The objective of this review is to discuss the new concepts of tissue engineering in endodontics and the clinical steps of root canal revascularization.

  16. Formation and separation of root border cells.

    Science.gov (United States)

    Driouich, Azeddine; Durand, Caroline; Vicré-Gibouin, Maïté

    2007-01-01

    Plant roots release a large number of border cells into the rhizosphere, which are believed to play a key role in root development and health. The formation and loss of these cells from the root cap region is a developmentally regulated process that is also controlled by phytohormones and environmental factors. The separation of border cells involves the complete dissociation of individual cells from each other and from root tissue. This process requires the activity of cell wall-degrading enzymes that solubilize the cell wall connections between cells. We present and discuss the solubilization process with an emphasis on pectin-degrading enzymes as well as the recently discovered root border-like cells of Arabidopsis thaliana.

  17. Nutrition and adventitious rooting in woody plants

    Directory of Open Access Journals (Sweden)

    Fernanda Bortolanza Pereira

    2016-09-01

    Full Text Available Vegetative propagation success of commercial genotypes via cutting techniques is related to several factors, including nutritional status of mother trees and of propagation material. The nutritional status determines the carbohydrate quantities, auxins and other compounds of plant essential metabolism for root initiation and development. Each nutrient has specific functions in plant, acting on plant structure or on plant physiology. Although the importance of mineral nutrition for success of woody plants vegetative propagation and its relation with adventitious rooting is recognized, the role of some mineral nutrients is still unknown. Due to biochemical and physiological complexity of adventitious rooting process, there are few researches to determine de role of nutrients on development of adventitious roots. This review intends to explore de state of the art about the effect of mineral nutrition on adventitious rooting of woody plants.

  18. The Complexity of Rooted Phylogeny Problems

    CERN Document Server

    Bodirsky, Manuel

    2011-01-01

    Several computational problems in phylogenetic reconstruction can be formulated as restrictions of the following general problem: given a formula in conjunctive normal form where the literals are rooted triples, is there a rooted binary tree that satisfies the formula? If the formulas do not contain disjunctions, the problem becomes the famous rooted triple consistency problem, which can be solved in polynomial time by an algorithm of Aho, Sagiv, Szymanski, and Ullman. If the clauses in the formulas are restricted to disjunctions of negated triples, Ng, Steel, and Wormald showed that the problem remains NP-complete. We systematically study the computational complexity of the problem for all such restrictions of the clauses in the input formula. For certain restricted disjunctions of triples we present an algorithm that has sub-quadratic running time and is asymptotically as fast as the fastest known algorithm for the rooted triple consistency problem. We also show that any restriction of the general rooted ph...

  19. Clinical management of infected root canal dentin.

    Science.gov (United States)

    Love, R M

    1996-08-01

    Several hundred different species of bacteria are present in the human intraoral environment. Bacterial penetration of root canal dentin occurs when bacteria invade the root canal system. These bacteria may constitute a reservoir from which root canal reinfection may occur during or after endodontic treatment. The learning objective of this article is to review endodontic microbiology, update readers on the role of bacteria in pulp and periapical disease, and discuss the principles of management of infected root canal dentin. Complete debridement, removal of microorganisms and affected dentin, and chemomechanical cleansing of the root canal are suggested as being the cornerstones of successful endodontic therapy, followed by intracanal medication to remove residual bacteria, when required.

  20. Effect of lead on root growth.

    Science.gov (United States)

    Fahr, Mouna; Laplaze, Laurent; Bendaou, Najib; Hocher, Valerie; Mzibri, Mohamed El; Bogusz, Didier; Smouni, Abdelaziz

    2013-01-01

    Lead (Pb) is one of the most widespread heavy metal contaminant in soils. It is highly toxic to living organisms. Pb has no biological function but can cause morphological, physiological, and biochemical dysfunctions in plants. Plants have developed a wide range of tolerance mechanisms that are activated in response to Pb exposure. Pb affects plants primarily through their root systems. Plant roots rapidly respond either (i) by the synthesis and deposition of callose, creating a barrier that stops Pb entering (ii) through the uptake of large amounts of Pb and its sequestration in the vacuole accompanied by changes in root growth and branching pattern or (iii) by its translocation to the aboveground parts of plant in the case of hyperaccumulators plants. Here we review the interactions of roots with the presence of Pb in the rhizosphere and the effect of Pb on the physiological and biochemical mechanisms of root development.

  1. Assessing the absorption of new pharmaceuticals.

    Science.gov (United States)

    Hidalgo, I J

    2001-11-01

    The advent of more efficient methods to synthesize and screen new chemical compounds is increasing the number of chemical leads identified in the drug discovery phase. Compounds with good biological activity may fail to become drugs due to insufficient oral absorption. Selection of drug development candidates with adequate absorption characteristics should increase the probability of success in the development phase. To assess the absorption potential of new chemical entities numerous in vitro and in vivo model systems have been used. Many laboratories rely on cell culture models of intestinal permeability such as, Caco-2, HT-29 and MDCK. To attempt to increase the throughput of permeability measurements, several physicochemical methods such as, immobilized artificial membrane (IAM) columns and parallel artificial membrane permeation assay (PAMPA) have been used. More recently, much attention has been given to the development of computational methods to predict drug absorption. However, it is clear that no single method will sufficient for studying drug absorption, but most likely a combination of systems will be needed. Higher throughput, less reliable methods could be used to discover 'loser' compounds, whereas lower throughput, more accurate methods could be used to optimize the absorption properties of lead compounds. Finally, accurate methods are needed to understand absorption mechanisms (efflux-limited absorption, carrier-mediated, intestinal metabolism) that may limit intestinal drug absorption. This information could be extremely valuable to medicinal chemists in the selection of favorable chemo-types. This review describes different techniques used for evaluating drug absorption and indicates their advantages and disadvantages.

  2. Quantum-enhanced absorption refrigerators

    CERN Document Server

    Correa, Luis A; Alonso, Daniel; Adesso, Gerardo

    2014-01-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step t...

  3. Acoustic Absorption in Porous Materials

    Science.gov (United States)

    Kuczmarski, Maria A.; Johnston, James C.

    2011-01-01

    An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

  4. Multistage quantum absorption heat pumps

    Science.gov (United States)

    Correa, Luis A.

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N -2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

  5. Multistage quantum absorption heat pumps.

    Science.gov (United States)

    Correa, Luis A

    2014-04-01

    It is well known that heat pumps, while being all limited by the same basic thermodynamic laws, may find realization on systems as "small" and "quantum" as a three-level maser. In order to quantitatively assess how the performance of these devices scales with their size, we design generalized N-dimensional ideal heat pumps by merging N-2 elementary three-level stages. We set them to operate in the absorption chiller mode between given hot and cold baths and study their maximum achievable cooling power and the corresponding efficiency as a function of N. While the efficiency at maximum power is roughly size-independent, the power itself slightly increases with the dimension, quickly saturating to a constant. Thus, interestingly, scaling up autonomous quantum heat pumps does not render a significant enhancement beyond the optimal double-stage configuration.

  6. Phytases for Improved Iron Absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Nyffenegger, Christian; Meyer, Anne S.

    2014-01-01

    Microbial phytases (EC 3.1.3.8) catalyse dephosphorylation of phytic acid, which is the primary storage compound for phosphorous in cereal kernels. The negatively charged phosphates in phytic acid chelate iron (Fe3+) and thus retards iron bioavailability in humans 1. Supplementation of microbial...... phytase can improve iron absorption from cereal-based diets 2. In order for phytase to catalyse iron release in vivo the phytase must be robust to low pH and proteolysis in the gastric ventricle. Our work has compared the robustness of five different microbial phytases, evaluating thermal stability......, activity retention, and extent of dephosphorylation of phytic acid in a simulated low pH/pepsin gastric environment. The five phytases responded differently to the robustness parameters: The Peniophora lycii phytase (Ronozyme NP) was the most thermostable, but the least robust enzyme at low pH, whereas...

  7. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  8. PHIV-RootCell: a supervised image analysis tool for rice root anatomical parameter quantification

    Directory of Open Access Journals (Sweden)

    Marc eLartaud

    2015-01-01

    Full Text Available We developed the PHIV-RootCell software to quantify anatomical traits of rice roots transverse section images. Combined with an efficient root sample processing method for image acquisition, this program permits supervised measurements of areas (those of whole root section, stele, cortex and central metaxylem vessels, number of cell layers and number of cells per cell layer. The PHIV-RootCell toolset runs under ImageJ, an independent operating system that has a license-free status. To demonstrate the usefulness of PHIV-RootCell, we conducted a genetic diversity study and an analysis of salt-stress responses of root anatomical parameters in rice (Oryza sativa L.. Using 16 cultivars, we showed that we could discriminate between some of the varieties even at the 6 day-old stage, and that tropical japonica varieties had larger root sections due to an increase in cell number. We observed, as described previously, that root sections become enlarged under salt stress. However, our results show an increase in cell number in ground tissues (endodermis and cortex but a decrease in external (peripheral tissues (sclerenchyma, exodermis and epidermis. Thus, the PHIV-RootCell program is a user-friendly tool that will be helpful for future genetic and physiological studies that investigate root anatomical trait variations.

  9. Root cap influences root colonisation by Pseudomonas fluorescens SBW25 on maize.

    Science.gov (United States)

    Humphris, Sonia N; Bengough, A Glyn; Griffiths, Bryan S; Kilham, Ken; Rodger, Sheena; Stubbs, Vicky; Valentine, Tracy A; Young, Iain M

    2005-09-01

    We investigated the influence of root border cells on the colonisation of seedling Zea mays roots by Pseudomonas fluorescens SBW25 in sandy loam soil packed at two dry bulk densities. Numbers of colony forming units (CFU) were counted on sequential sections of root for intact and decapped inoculated roots grown in loose (1.0 mg m(-3)) and compacted (1.3 mg m(-3)) soil. After two days of root growth, the numbers of P. fluorescens (CFU cm(-1)) were highest on the section of root just below the seed with progressively fewer bacteria near the tip, irrespective of density. The decapped roots had significantly more colonies of P. fluorescens at the tip compared with the intact roots: approximately 100-fold more in the loose and 30-fold more in the compact soil. In addition, confocal images of the root tips grown in agar showed that P. fluorescens could only be detected on the tips of the decapped roots. These results indicated that border cells, and their associated mucilage, prevented complete colonization of the root tip by the biocontrol agent P. fluorescens, possibly by acting as a disposable surface or sheath around the cap.

  10. Aerenchyma Formed Under Phosphorus Deficiency Contributes to the Reduced Root Hydraulic Conductivity in Maize Roots

    Institute of Scientific and Technical Information of China (English)

    Mingshou Fan; Ruiqin Bai; Xuefeng Zhao; Jianhua Zhang

    2007-01-01

    Root hydraulic conductivity has been shown to decrease under phosphorus (P) deficiency. This study investigated how the formation of aerenchyma is related to this change. Root anatomy, as well as root hydraulic conductivity was studied in maize (Zea mays L.) roots under different phosphorus nutrition conditions. Plant roots under P stress showed enhanced degradation of cortical cells and the aerenchyma formation was associated with their reduced root hydraulic conductivity, supporting our hypothesis that air spaces that form in the cortex of phosphorusstressed roots impede the radial transport of water in a root cylinder. Further evidence came from the variation in aerenchyma formation due to genotypic differences. Five maize inbred lines with different porosity in their root cortex showed a significant negative correlation with their root hydraulic conductivity. Shoot relative water content was also found lower in P-deficient maize plants than that in P-sufficient ones when such treatment was prolonged enough, suggesting a limitation of water transport due to lowered root hydraulic conductivity of P-deficient piants.

  11. Resistance to compression of weakened roots subjected to different root reconstruction protocols

    Directory of Open Access Journals (Sweden)

    Lucas Villaça Zogheib

    2011-12-01

    Full Text Available OBJECTIVE: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. MATERIAL AND METHODS: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10, according to the root reconstruction protocol: Group I (control: non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45º in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (α=0.05. RESULTS: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. CONCLUSION: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

  12. RootGraph: a graphic optimization tool for automated image analysis of plant roots.

    Science.gov (United States)

    Cai, Jinhai; Zeng, Zhanghui; Connor, Jason N; Huang, Chun Yuan; Melino, Vanessa; Kumar, Pankaj; Miklavcic, Stanley J

    2015-11-01

    This paper outlines a numerical scheme for accurate, detailed, and high-throughput image analysis of plant roots. In contrast to existing root image analysis tools that focus on root system-average traits, a novel, fully automated and robust approach for the detailed characterization of root traits, based on a graph optimization process is presented. The scheme, firstly, distinguishes primary roots from lateral roots and, secondly, quantifies a broad spectrum of root traits for each identified primary and lateral root. Thirdly, it associates lateral roots and their properties with the specific primary root from which the laterals emerge. The performance of this approach was evaluated through comparisons with other automated and semi-automated software solutions as well as against results based on manual measurements. The comparisons and subsequent application of the algorithm to an array of experimental data demonstrate that this method outperforms existing methods in terms of accuracy, robustness, and the ability to process root images under high-throughput conditions.

  13. Effects of Gyroresonance Absorption and Self Absorption on the Gyrosynchrotron Radiation Spectrum

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ai-Hua; SU Ying-Na; HUANG Guang-Li

    2004-01-01

    Effects of gyroresonance absorption and self absorption on the gyrosynchrotron radiation spectrum are investi gated with a model in a magnetic dipole field. It is found that the gyroresonance absorption and self absorption suppress substantially the gyrosynchrotron radiation at lower frequencies where the radio source is optically thick.The suppression of the gyroresonance absorption on the spectrum increases with the increasing temperature and density of thermal electrons. The suppression of the self absorption on the spectrum increases as increasing number density of the nonthermal electrons. The influences of the gyroresonance absorption and the self one on the spectrum are compared quantitatively. It is shown that only when the number density of the nonthermal electron reaches a higher value of about 3 × 104 cm-3 above 10keV, can the effect of the self absorption on the spectrum compare with the effect of the gyroresonance absorption.

  14. Root phenology at Harvard Forest and beyond

    Science.gov (United States)

    Abramoff, R. Z.; Finzi, A.

    2013-12-01

    Roots are hidden from view and heterogeneously distributed making them difficult to study in situ. As a result, the causes and timing of root production are not well understood. Researchers have long assumed that above and belowground phenology is synchronous; for example, most parameterizations of belowground carbon allocation in terrestrial biosphere models are based on allometry and represent a fixed fraction of net C uptake. However, using results from metaanalysis as well as empirical data from oak and hemlock stands at Harvard Forest, we show that synchronous root and shoot growth is the exception rather than the rule. We collected root and shoot phenology measurements from studies across four biomes (boreal, temperate, Mediterranean, and subtropical). General patterns of root phenology varied widely with 1-5 production peaks in a growing season. Surprisingly, in 9 out of the 15 studies, the first root production peak was not the largest peak. In the majority of cases maximum shoot production occurred before root production (Offset>0 in 32 out of 47 plant sample means). The number of days offset between maximum root and shoot growth was negatively correlated with median annual temperature and therefore differs significantly across biomes (ANOVA, F3,43=9.47, pGrowth form (woody or herbaceous) also influenced the relative timing of root and shoot growth. Woody plants had a larger range of days between root and shoot growth peaks as well as a greater number of growth peaks. To explore the range of phenological relationships within woody plants in the temperate biome, we focused on above and belowground phenology in two common northeastern tree species, Quercus rubra and Tsuga canadensis. Greenness index, rate of stem growth, root production and nonstructural carbohydrate content were measured beginning in April 2012 through August 2013 at the Harvard Forest in Petersham, MA, USA. Greenness and stem growth were highest in late May and early June with one clear

  15. Effect of lipid/polysaccharide ratio on surface activity of model root mucilage in its solid and liquid states

    Science.gov (United States)

    Chen, Fengxian; Arye, Gilboa

    2016-04-01

    The rhizosphere can be defined as the volume of soil around living roots, which is influenced by root activity. The biological, chemical and physical conditions that prevail in the rhizosphere are significantly different from those of the bulk soil. Plant roots can release diverse organic materials in the rhizosphere which may have different effects on its bio-chemo-physical activity. Among these exudates is the root mucilage which can play a role on the maintenance of root-soil contact, lubrication of the root tip, protection of roots from desiccation and disease, stabilization of soil micro-aggregates and the selective absorption and storage of ions. The surface activity of the root mucilage at the liquid-air interface deduced from its surface tension depression relative to water, implying on its amphiphilic nature. Consequently as the rhizosphere dry out, hydrophobic functional groups may exhibit orientation at the solid-air interface and thus, the wettability of the rhizosphere may temporarily decrease. The major fraction of the root mucilage comprise of polysaccharides and to a much lesser extent, amino acids, organic acids, and phospholipids. The most frequent polysaccharide and phospholipids detected in root mucilage are polygalacturonic acid (PGA) and Phosphatidylcholine (PC), respectively. The latter, is thought to be main cause for the surface active nature of root mucilage. Nevertheless, the role and function of root mucilage in the rhizosphere is commonly studied based on model root mucilage that comprise of only one component, where the most frequent ones are PGA or PC (or lecithin). The main objective of this study was to quantify the effect of concentration and PGA/PC ratios on the wettability of a model rhizosphere soil and the surface tension of the model root mucilage at the liquid-air interface. The PGA/PC mixtures were measured for their equilibrium and dynamic surface tension using the Wilhelmy-Plate method. Quartz sand or glass slides were

  16. Lyman-alpha Absorption from Heliosheath Neutrals

    CERN Document Server

    Wood, B E; Linsky, J L; Malama, Y G; Wood, Brian E.; Izmodenov, Vladislav V.; Linsky, Jeffrey L.; Malama, Yury G.

    2006-01-01

    We assess what information HST observations of stellar Ly-alpha lines can provide on the heliosheath, the region of the heliosphere between the termination shock and heliopause. To search for evidence of heliosheath absorption, we conduct a systematic inspection of stellar Ly-alpha lines reconstructed after correcting for ISM absorption (and heliospheric/astrospheric absorption, if present). Most of the stellar lines are well centered on the stellar radial velocity, as expected, but the three lines of sight with the most downwind orientations relative to the ISM flow (Chi1 Ori, HD 28205, and HD 28568) have significantly blueshifted Ly-alpha lines. Since it is in downwind directions where heliosheath absorption should be strongest, the blueshifts are almost certainly caused by previously undetected heliosheath absorption. We make an initial comparison between the heliosheath absorption and the predictions of a pair of heliospheric models. A model with a complex multi-component treatment of plasma within the he...

  17. Impact of transporters in oral absorption

    DEFF Research Database (Denmark)

    Gram, Luise K; Rist, Gerda Marie; Steffansen, Bente

    2009-01-01

    was to investigate whether transporters were involved in the intestinal absorption of an organic anion A275 and to compare the impact of interactions related to transporters in the Caco-2 cell model versus the in vivo rat model of intestinal absorption. In both models, it was investigated whether intestinal...... permeation of A275 was concentration dependent and affected by inhibitors or competitive organic anions. Interactions related to transporters in intestinal permeation was clearly demonstrated in the Caco-2 cell model but was not directly evident for in vivo rat absorption. However, an observed biphasic...... in vivo absorption and a large intervariability between rats might mask a dose-dependent absorption of A275. To avoid these suggested interactions, a dose of at least 10 mg/kg, which saturates the intestinal transporters involved in A275 absorption, should be administered, but at doses below that the risk...

  18. Analysis of frequency dependent pump light absorption

    Science.gov (United States)

    Wohlmuth, Matthias; Pflaum, Christoph

    2011-03-01

    Simulations have to accurately model thermal lensing in order to help improving resonator design of diode pumped solid state lasers. To this end, a precise description of the pump light absorption is an important prerequisite. In this paper, we discuss the frequency dependency of the pump light absorption in the laser crystal and its influence on the simulated laser performance. The results show that the pump light absorption has to include the spectral overlap of the emitting pump source and the absorbing laser material. This information can either be used for a fully frequency dependent absorption model or, at least in the shown examples, to compute an effective value for an exponential Beer-Lambert law of absorption. This is particularly significant at pump wavelengths coinciding with a peak of absorption. Consequences for laser stability and performance are analyzed for different pump wavelengths in a Nd:YAG laser.

  19. Atomic absorption spectroscopy in ion channel screening.

    Science.gov (United States)

    Stankovich, Larisa; Wicks, David; Despotovski, Sasko; Liang, Dong

    2004-10-01

    This article examines the utility of atomic absorption spectroscopy, in conjunction with cold flux assays, to ion channel screening. The multiplicity of ion channels that can be interrogated using cold flux assays and atomic absorption spectroscopy is summarized. The importance of atomic absorption spectroscopy as a screening tool is further elaborated upon by providing examples of the relevance of ion channels to various physiological processes and targeted diseases.

  20. Absorption boundary conditions for geomertical acoustics

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2012-01-01

    Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, the absorption coefficients or surface impedances of the boundary surfaces can be used, but no guideline has been developed...... solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. It is concluded that the impedance and random incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials....

  1. Root distribution of rootstocks for 'Tahiti' lime

    Directory of Open Access Journals (Sweden)

    Neves Carmen Silvia Vieira Janeiro

    2004-01-01

    Full Text Available Field studies on citrus roots are important for genetic selection of cultivars and for management practices such as localized irrigation and fertilization. To characterize root systems of six rootstocks, taking into consideration chemical and physical characteristics of a clayey Typic Hapludox of the Northern State of Paraná, this study was performed having as scion the 'IAC-5 Tahiti' lime [Citrus latifolia (Yu. Tanaka]. The rootstocks 'Rangpur' lime (C. limonia Osbeck, 'Africa Rough' lemon (C. jambhiri Lush., 'Sunki' mandarin [C. sunki (Hayata hort. ex Tan.], Poncirus trifoliata (L. Raf., 'C13' citrange [C. sinensis (L. Osb. x P. trifoliata (L. Raf] and 'Catânia 2' Volkamer lemon (C. volkameriana Ten. & Pasq. were used applying the trench profile method and the SIARCS® 3.0 software to determine root distribution. 'C-13' citrange had the largest root system. 'Volkamer' lemon and 'Africa Rough' lemon presented the smallest amount of roots. The effective depth for 80 % of roots was 31-53 cm in rows and 67-68 cm in inter-rows. The effective distance of 80 % of roots measured from the tree trunk exceeded the tree canopy for P. trifoliata, 'Sunki' mandarin, and 'Volkamer' and 'Africa Rough' lemons.

  2. A thermodynamic formulation of root water uptake

    Science.gov (United States)

    Hildebrandt, Anke; Kleidon, Axel; Bechmann, Marcel

    2016-08-01

    By extracting bound water from the soil and lifting it to the canopy, root systems of vegetation perform work. Here we describe how root water uptake can be evaluated thermodynamically and demonstrate that this evaluation provides additional insights into the factors that impede root water uptake. We derive an expression that relates the energy export at the base of the root system to a sum of terms that reflect all fluxes and storage changes along the flow path in thermodynamic terms. We illustrate this thermodynamic formulation using an idealized setup of scenarios with a simple model. In these scenarios, we demonstrate why heterogeneity in soil water distribution and rooting properties affect the impediment of water flow even though the mean soil water content and rooting properties are the same across the scenarios. The effects of heterogeneity can clearly be identified in the thermodynamics of the system in terms of differences in dissipative losses and hydraulic energy, resulting in an earlier start of water limitation in the drying cycle. We conclude that this thermodynamic evaluation of root water uptake conveniently provides insights into the impediments of different processes along the entire flow path, which goes beyond resistances and also accounts for the role of heterogeneity in soil water distribution.

  3. Spiralizations and tropisms in Arabidopsis roots.

    Science.gov (United States)

    Migliaccio, F; Piconese, S

    2001-12-01

    When Arabidopsis seedlings are grown on a hard-agar plate, their primary roots show characteristic spiralling movements, apparent as waves, coils and torsions, together with a slanting toward the right-hand side. All these movements are believed to be the result of three different processes acting on the roots: circumnutation, positive gravitropism and negative thigmotropism. The basic movement of the roots is described as that of a growing right-handed helix, which, because of the root tip hitting the agar plate, is continuously switched from the right-hand to the left-hand of the growth direction, and vice versa. This movement also produces a slanting root-growth direction toward the right-hand because of the incomplete waves made by the right-handed root to the left-hand. By contrast, the torsions seen in the coils and waves are interpreted as artefacts that form as an adaptation of the three-dimensional root helix to the flat two-dimensional agar surface.

  4. Tractography of lumbar nerve roots: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Balbi, Vincent; Budzik, Jean-Francois; Thuc, Vianney le; Cotten, Anne [Hopital Roger Salengro, Service de Radiologie et d' Imagerie musculo-squelettique, Lille Cedex (France); Duhamel, Alain [Universite de Lille 2, UDSL, Lille (France); Bera-Louville, Anne [Service de Rhumatologie, Hopital Roger Salengro, Lille (France)

    2011-06-15

    The aims of this preliminary study were to demonstrate the feasibility of in vivo diffusion tensor imaging (DTI) and fibre tracking (FT) of the lumbar nerve roots, and to assess potential differences in the DTI parameters of the lumbar nerves between healthy volunteers and patients suffering from disc herniation. Nineteen patients with unilateral sciatica related to posterolateral or foraminal disc herniation and 19 healthy volunteers were enrolled in this study. DTI with tractography of the L5 or S1 nerves was performed. Mean fractional anisotropy (FA) and mean diffusivity (MD) values were calculated from tractography images. FA and MD values could be obtained from DTI-FT images in all controls and patients. The mean FA value of the compressed lumbar nerve roots was significantly lower than the FA of the contralateral nerve roots (p=0.0001) and of the nerve roots of volunteers (p=0.0001). MD was significantly higher in compressed nerve roots than in the contralateral nerve root (p=0.0002) and in the nerve roots of volunteers (p=0.04). DTI with tractography of the lumbar nerves is possible. Significant changes in diffusion parameters were found in the compressed lumbar nerves. (orig.)

  5. Neural regulation of intestinal nutrient absorption.

    Science.gov (United States)

    Mourad, Fadi H; Saadé, Nayef E

    2011-10-01

    The nervous system and the gastrointestinal (GI) tract share several common features including reciprocal interconnections and several neurotransmitters and peptides known as gut peptides, neuropeptides or hormones. The processes of digestion, secretion of digestive enzymes and then absorption are regulated by the neuro-endocrine system. Luminal glucose enhances its own absorption through a neuronal reflex that involves capsaicin sensitive primary afferent (CSPA) fibres. Absorbed glucose stimulates insulin release that activates hepatoenteric neural pathways leading to an increase in the expression of glucose transporters. Adrenergic innervation increases glucose absorption through α1 and β receptors and decreases absorption through activation of α2 receptors. The vagus nerve plays an important role in the regulation of diurnal variation in transporter expression and in anticipation to food intake. Vagal CSPAs exert tonic inhibitory effects on amino acid absorption. It also plays an important role in the mediation of the inhibitory effect of intestinal amino acids on their own absorption at the level of proximal or distal segment. However, chronic extrinsic denervation leads to a decrease in intestinal amino acid absorption. Conversely, adrenergic agonists as well as activation of CSPA fibres enhance peptides uptake through the peptide transporter PEPT1. Finally, intestinal innervation plays a minimal role in the absorption of fat digestion products. Intestinal absorption of nutrients is a basic vital mechanism that depends essentially on the function of intestinal mucosa. However, intrinsic and extrinsic neural mechanisms that rely on several redundant loops are involved in immediate and long-term control of the outcome of intestinal function.

  6. Absorption events associated with solar flares

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    During the upward period of solar cycle 23, the imaging riometer at Zhongshan, Antarctica (geomag. lat. 74.5°S) was used to study the solar proton events and the X-ray solar flares which are associated with the absorption events. In our study, the relationship between the absorption intensity and X-ray flux is found in a power form which is consistent with the theoretical result. The imaging riometer absorption data at Ny-?lesund, Svalbard reconfirm the above relationship. We also argue that only M-class flares can generate a significant daytime absorption.

  7. Emission and Absorption Entropy Generation in Semiconductors

    DEFF Research Database (Denmark)

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika

    2013-01-01

    While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor...... materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...

  8. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We developed a highly sensitive and compact instrument to directly measure particulate matter (PM) optical absorption. This device is based on differential...

  9. [Adaptive adjustment of rhizome and root system on morphology, biomass and nutrient in Phyllostachys rivalis under long-term waterlogged condition].

    Science.gov (United States)

    Liu, Yu-fang; Chen, Shuang-lin; Li Ying-chun; Guo, Zi-wu; Li, Ying-chun; Yang, Qing-ping

    2015-12-01

    The research was to approach the growth strategy of rhizome and roots based on the morphology, biomass and nutrient in Phyllostachys rivalis under long-term waterlogged conditions, and provided a theoretical basis for its application for vegetation restoration in wetland and water-level fluctuation belts. The morphological characteristics, physiological and biochemical indexes of annual bamboo rhizome and roots were investigated with an experiment using individually potted P. rivalis which was treated by artificial water-logging for 3, 6, and 12 months. Accordingly the morphological characteristics, biomass allocation, nutrient absorption and balance in rhizome and roots of P. rivalis were analyzed. The results showed that there was no obvious impact of long-term water-logging on the length and diameter of rhizomes, diameter of roots in P. rivalis. The morphological characteristics of rhizome had been less affected generally under water-logging for 3 months. And less rhizomes were submerged, while the growth of roots was inhibited to some extent. Furthermore, with waterlogging time extended, submerged roots and rhizomes grew abundantly, and the roots and rhizomes in soil were promoted. Moreover for ratios of rhizome biomass in soil and water, there were no obvious variations, the same for the root biomass in soil to total biomass. The ratio of root biomass in water to total biomass and the ratio of root biomass in water to root biomass in soil both increased significantly. The results indicated that P. rivalis could adapt to waterlogged conditions gradually through growth regulation and reasonable biomass distribution. However, the activity of rhizome roots in soil decreased and the nutrient absorption was inhibited by long-term water-logging, although it had no effect on stoichiometric ratios of root nutrient in soil. The activity of rhizome root in water increased and the stoichiometric ratios adjusted adaptively to waterlogged conditions, the ratio of N

  10. 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

  11. Localization an speciation of Zn in mycorrhized roots by μSXRF and μEXAFS

    Science.gov (United States)

    Sarret, G.; Schroeder, W. H.; Marcus, M. A.; Geoffroy, N.; Manceau, A.

    2003-05-01

    Mycorrhizae are symbiotic associations between soil fungi and plant mots, which enhance mineral nutrition for the plant, and might play an important role in metals acquisition and accumulation. The processes allowing metals mobilizaiion in the soil, absorption by the root and/or the fungus, transfert or bioaccumulation we still poorly understood. However, the properties of mycorrhizal fungi could be used for phytoremediation, a soft technique using plants for the clean-up of metal polluted soils. In this work, mycorrhized roots of tomato plants grown in a Zn-contaminated sail were investigated. The distribution of metals and the speciation of Zn were studied at the micron scale using micro synchrotron-based X-ray fluorescence (μSXRF) and micro X-ray absorption spectroscopy (μEXAFS). Zn associated to the root was Zn malate and/or Zn citrate, and Zn associated to the fungus was Zn phyllosilicate. This study illustrates the great potential of X-ray microbeams for the study of biological samples containing various amounts of metals.

  12. Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

    Science.gov (United States)

    Sarp, Ayşe. S.; Gülsoy, Murat

    2016-02-01

    Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p < 0.05, Mann- U-Whitney Test). In addition to this, Er :YAG Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

  13. Root type matters: measurements of water uptake by seminal, crown and lateral roots of maize

    Science.gov (United States)

    Ahmed, Mutez Ali; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

    2016-04-01

    Roots play a key role in water acquisition and are a significant component of plant adaptation to different environmental conditions. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of root water uptake in mature maize. We used neutron radiography to image the spatial distribution of maize roots and trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers filled with a sandy soil that was kept homogeneously wet throughout the experiment. When the plants were five weeks-old, we injected D2O into selected soil regions. The transport of D2O was simulated using a diffusion-convection numerical model. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The model was initially developed and tested with two weeks-old maize (Ahmed et. al. 2015), for which we found that water was mainly taken up by lateral roots and the water uptake of the seminal roots was negligible. Here, we used this method to measure root water uptake in a mature maize root system. The root architecture of five weeks-old maize consisted of primary and seminal roots with long laterals and crown (nodal) roots that emerged from the above ground part of the plant two weeks after planting. The crown roots were thicker than the seminal roots and had fewer and shorter laterals. Surprisingly, we found that the water was mainly taken up by the crown roots and their laterals, while the lateral roots of seminal roots, which were the main location of water uptake of younger plants, stopped to take up water. Interestingly, we also found that in contrast to the seminal roots, the crown roots were able to take up water also from their distal segments. We conclude that for the two weeks

  14. Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling

    Science.gov (United States)

    Schwarz, M.; Cohen, D.; Or, D.

    2011-06-01

    Root-soil mechanical interactions are key to soil stability on steep hillslopes. Motivated by new advances and applications of the Root Bundle Model (RBM), we conducted a series of experiments in the laboratory and in the field to study the mechanical response of pulled roots. We systematically quantified the influence of different factors such as root geometry and configuration, soil type, and soil water content considering individual roots and root bundles. We developed a novel pullout apparatus for strain-controlled field and laboratory tests of up to 13 parallel roots measured individually and as a bundle. Results highlight the importance of root tortuosity and root branching points for prediction of individual root pullout behavior. Results also confirm the critical role of root diameter distribution for realistic prediction of global pullout behavior of a root bundle. Friction between root and soil matrix varied with soil type and water content and affected the force-displacement behavior. Friction in sand varied from 1 to 17 kPa, with low values obtained in wet sand at a confining pressure of 2 kPa and high values obtained in dry sand with 4.5 kPa confining pressure. In a silty soil matrix, friction ranged between 3 kPa under wet and low confining pressure (2 kPa) and 6 kPa in dry and higher confining pressure (4.5 kPa). Displacement at maximum pullout force increased with increasing root diameter and with tortuosity. Laboratory experiments were used to calibrate the RBM that was later validated using six field measurements with natural root bundles of Norway spruce (Picea abies L.). These tests demonstrate the progressive nature of root bundle failure under strain-controlled pullout force and provide new insights regarding force-displacement behavior of root reinforcement, highlighting the importance of considering displacement in slope stability models. Results show that the magnitude of maximum root pullout forces (1-5 kPa) are important for slope

  15. A "square-root rule" for reinsurance

    Directory of Open Access Journals (Sweden)

    Michael R. Powers

    2006-12-01

    Full Text Available In previous work, the authors derived a mathematical expression for the optimal (or "saturation" number of reinsurers for a given number of primary insurers (see Powers and Shubik, 2001. In the current article, we show analytically that, for large numbers of primary insurers, this mathematical expression provides a "square-root rule"; i.e., the optimal number of reinsurers in a market is given asymptotically by the square root of the total number of primary insurers. We note further that an analogous "fourth-root rule" applies to markets for retrocession (the reinsurance of reinsurance.

  16. Clinical technique for invasive cervical root resorption

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Machado Silveira

    2011-01-01

    Full Text Available This clinical case report describes the diagnosis and treatment of an external invasive cervical resorption. A 17-year-old female patient had a confirmed diagnosis of invasive cervical resorption class 4 by cone beam computerized tomography. Although, there was no communication with the root canal, the invasive resorption process was extending into the cervical and middle third of the root. The treatment of the cervical resorption of the lateral incisor interrupted the resorptive process and restored the damaged root surface and the dental functions without any esthetic sequelae. Both the radiographic examination and computed tomography are imperative to reveal the extent of the defect in the differential diagnosis.

  17. ANTIARTHRITIC ACTIVITY OF DESMODIUM GANGETICUM ROOT

    Directory of Open Access Journals (Sweden)

    Vedpal

    2013-09-01

    Full Text Available The present study is aimed to evaluate the in-vitro anti-arthritic activity of aqueous extract of Desmodium gangeticum root using inhibition of protein denaturation model and human red blood cell Membrane stabilization model. Diclofenac sodium was used as a standard drug. Results revealed that the aqueous extract of Desmodium gangeticum root at different concentrations possessed significant anti-arthritic activity as compared to standard drug used as Diclofenac sodium. The results obtained in the present investigation Indicate that aqueous extract of Desmodium gangeticum root showed anti-arthritic activity.

  18. BOREAS TE-2 Root Respiration Data

    Science.gov (United States)

    Ryan, Michael G.; Lavigne, Michael; Hall, Forrest G. (Editor); Papagno, Andrea (Editor)

    2000-01-01

    The BOREAS TE-2 team collected several data sets in support of its efforts to characterize and interpret information on the respiration of the foliage, roots, and wood of boreal vegetation. This data set includes means of tree root respiration measurements on roots having diameters ranging from 0 to 2 mm conducted in the NSA during the growing season of 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  19. THttpServer class in ROOT

    Science.gov (United States)

    Adamczewski-Musch, Joern; Linev, Sergey

    2015-12-01

    The new THttpServer class in ROOT implements HTTP server for arbitrary ROOT applications. It is based on Civetweb embeddable HTTP server and provides direct access to all objects registered for the server. Objects data could be provided in different formats: binary, XML, GIF/PNG, and JSON. A generic user interface for THttpServer has been implemented with HTML/JavaScript based on JavaScript ROOT development. With any modern web browser one could list, display, and monitor objects available on the server. THttpServer is used in Go4 framework to provide HTTP interface to the online analysis.

  20. Negative phototropism of rice root and its influencing factors

    Institute of Scientific and Technical Information of China (English)

    WANG; Zhong(王忠); MO; Yiwei(莫亿伟); QIAN; Shanqin(钱善勤); GU; Yunjie(顾蕴洁)

    2002-01-01

    Some characteristics of the rice (Oryza sativa L.) root were found in the experiment of unilaterally irradiating the roots which were planted in water: (ⅰ) All the seminal roots, adventitious roots and their branched roots bent away from light, and their curvatures ranged from 25° to 60°. The curvature of adventitious root of the higher node was often larger than that of the lower node, and even larger than that of the seminal root. (ⅱ) The negative phototropic bending of the rice root was mainly due to the larger growth increment of root-tip cells of the irradiated side compared with that of the shaded side. (ⅲ) Root cap was the site of light perception. If root cap was shaded while the root was irradiated the root showed no negative phototropism, and the root lost the characteristic of negative phototropism when root cap was divested. Rice root could resume the characteristic of negative phototropism when the new root cap grew up, if the original cells of root cap were well protected while root cap was divested. (ⅳ) The growth increment and curvature of rice root were both influenced by light intensity. Within the range of 0-100μmol@m-2@s-1, the increasing of light intensity resulted in the decreasing of the growth increment and the increasing of the curvature of rice root. (ⅴ) The growth increment and the curvature reached the maximum at 30℃ with the temperature treatment of 10-40℃. (ⅵ) Blue-violet light could prominently induce the negative phototropism of rice root, while red light had no such effect. (ⅶ) The auxin (IAA) in the solution, as a very prominent influencing factor, inhibited the growth, the negative phototropism and the gravitropism of rice root when the concentration of IAA increased. The response of negative phototropism of rice root disappeared when the concentration of IAA was above 10 mg@L-1.

  1. Arabidopsis: an adequate model for dicot root systems?

    OpenAIRE

    Zobel, Richard W.

    2016-01-01

    The Arabidopsis root system is frequently considered to have only three classes of root: primary, lateral, and adventitious. Research with other plant species has suggested up to 8 different developmental/functional classes of root for a given plant root system. If Arabidopsis has only three classes of root, it may not be an adequate model for eudicot plant root systems. Recent research, however, can be interpreted to suggest that pre-flowering Arabidopsis does have at least five (5) of th...

  2. Arabidopsis: An Adequate Model for Dicot Root Systems?

    OpenAIRE

    Zobel, Richard W.

    2016-01-01

    The Arabidopsis root system is frequently considered to have only three classes of root: primary, lateral, and adventitious. Research with other plant species has suggested up to eight different developmental/functional classes of root for a given plant root system. If Arabidopsis has only three classes of root, it may not be an adequate model for eudicot plant root systems. Recent research, however, can be interpreted to suggest that pre-flowering Arabidopsis does have at least five (5) of t...

  3. Genetic dissection of nitrogen nutrition in pea through a QTL approach of root, nodule, and shoot variability.

    Science.gov (United States)

    Bourion, Virginie; Rizvi, Syed Masood Hasan; Fournier, Sarah; de Larambergue, Henri; Galmiche, Fabien; Marget, Pascal; Duc, Gérard; Burstin, Judith

    2010-06-01

    Pea (Pisum sativum L.) is the third most important grain legume worldwide, and the increasing demand for protein-rich raw material has led to a great interest in this crop as a protein source. Seed yield and protein content in crops are strongly determined by nitrogen (N) nutrition, which in legumes relies on two complementary pathways: absorption by roots of soil mineral nitrogen, and fixation in nodules of atmospheric dinitrogen through the plant-Rhizobium symbiosis. This study assessed the potential of naturally occurring genetic variability of nodulated root structure and functioning traits to improve N nutrition in pea. Glasshouse and field experiments were performed on seven pea genotypes and on the 'Cameor' x 'Ballet' population of recombinant inbred lines selected on the basis of parental contrast for root and nodule traits. Significant variation was observed for most traits, which were obtained from non-destructive kinetic measurements of nodulated root and shoot in pouches, root and shoot image analysis, (15)N quantification, or seed yield and protein content determination. A significant positive relationship was found between nodule establishment and root system growth, both among the seven genotypes and the RIL population. Moreover, several quantitative trait loci for root or nodule traits and seed N accumulation were mapped in similar locations, highlighting the possibility of breeding new pea cultivars with increased root system size, sustained nodule number, and improved N nutrition. The impact on both root or nodule traits and N nutrition of the genomic regions of the major developmental genes Le and Af was also underlined.

  4. Phosphate Availability Alters Lateral Root Anatomy and Root Architecture of Fraxinus mandshurica Rupr. Seedlings

    Institute of Scientific and Technical Information of China (English)

    Chu WU; Xing WEI; Hai-Long SUN; Zheng-Quan WANG

    2005-01-01

    Plants have evolved some mechanisms to maximize the efficiency of phosphorus acquisition.Changes in root architecture are one such mechanism. When Fraxinus mandshurica Rupr. seedlings were grown under conditions of low phosphorus availability, the length of cells in the meristem zone of the lateral roots was longer, but the length of cells in the elongation and mature zones of the lateral roots was shorter,compared with seedlings grown under conditions of high phosphorus availability. The elongation rates of primary roots increased as phosphorus availability increased, but the elongation rates of the branched zones of the primary roots decreased. The number of lateral root primordia and the length of the lateral roots decreased as phosphorus availability increased. The topological index (altitude slope) decreased as phosphorus availability increased, suggesting that root architecture tended to be herringbone-like when seedlings were grown under conditions of low phosphate availability. Herringbone-like root systems exploit nutrients more efficiently, but they have higher construction costs than root systems with a branching pattern.

  5. 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.

  6. Plant roots use a patterning mechanism to position lateral root branches toward available water.

    Science.gov (United States)

    Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

    2014-06-24

    The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

  7. Rooting depths of plants relative to biological and environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Foxx, T S; Tierney, G D; Williams, J M

    1984-11-01

    In 1981 to 1982 an extensive bibliographic study was completed to document rooting depths of native plants in the United States. The data base presently contains 1034 citations with approximately 12,000 data elements. In this paper the data were analyzed for rooting depths as related to life form, soil type, geographical region, root type, family, root depth to shoot height ratios, and root depth to root lateral ratios. Average rooting depth and rooting frequencies were determined and related to present low-level waste site maintenance.

  8. The absorption of polymeric composites

    Science.gov (United States)

    Řídký, R.; Popovič, M.; Rolc, S.; Drdlová, M.; Krátký, J.

    2016-06-01

    An absorption capacity of soft, viscoelastic materials at high strain rates is important for wide range of practical applications. Nowadays there are many variants of numerical models suitable for this kind of analysis. The main difficulty is in selection of the most realistic numerical model and a correct setup of many unknown material constants. Cooperation between theoretical simulations and real testing is next crucial point in the investigation process. Standard open source material database offer material properties valid for strain rates less than 250 s-1. There are experiments suitable for analysis of material properties with strain rates close to 2000 s-1. The high strain-rate characteristics of a specific porous blast energy absorbing material measured by modified Split Hopkinson Pressure Bar apparatus is presented in this study. Testing these low impedance materials using a metallic split Hopkinson pressure bar setup results in poor signal to noise ratios due to impedance mismatching. These difficulties are overcome by using polymeric Hopkinson bars. Conventional Hopkinson bar analysis cannot be used on the polymeric bars due to the viscoelastic nature of the bar material. One of the possible solution leads to complex and frequency depended Young modulus of testing bars material. This testing technique was applied to materials composed of porous glass/ceramic filler and polymeric binder, with density of 125 - 300 kg/m3 and particle size in range of 50 µm - 2 mm. The achieved material model was verified in practical application of sandwich structure includes polymeric composites under a blast test.

  9. Effect of two contemporary root canal sealers on root canal dentin microhardness

    Science.gov (United States)

    2017-01-01

    Background Successful root canal treatment depends on proper cleaning, disinfecting and shaping of the root canal space. Pulpless teeth have lower dentin microhardness value compared to that of vital teeth. A material which can cause change in dentin composition may affect the microhardness. Thus the aim of this study was to evaluate and compare the effect of two root canal sealers on dentin microhardness. Material and Methods Forty two single rooted teeth were selected and divided into 3 equal groups; Apexit, iRootSP and control groups (n=14) Each group was then divided into 2 subgroups according to the post evaluation period; 1 week and 2 months (n=7). Root canal procedure was done in the experimental groups and obturation was made using either; Apexit, iRootSP or left unprepared and unobturated in the control group. Roots were sectioned transversely into cervical, middle and apical segments. The three sections of each root were mounted in a plastic chuck with acrylic resin. The coronal dentin surfaces of the root segments werepolished. Microhardness of each section was measured at 500 µm and 1000 µm from the canal lumen. Results Four way-ANOVA revealed that different tested sealer materials, canal third, measuring distance from the pulp and time as independent variables had statistically non significant effect on mean microhardness values (VHN) at p≤0.001. Among iRootSP groups there was a statistically significant difference between iRoot SP at coronal root portion (87.79±17.83) and iRoot SP at apical root portion (76.26±9.33) groups where (p=0.01). IRoot SP at coronal canal third had higher statistically significant mean microhardness value (87.79±17.83) compared to Apexit at coronal third (73.61±13.47) where (p=0.01). Conclusions Root canal sealers do not affect dentin microhardness. Key words:Root canal, dentin, sealers, microhardness, bioceramic. PMID:28149466

  10. DMA thermal analysis of yacon tuberous roots

    Science.gov (United States)

    Blahovec, J.; Lahodová, M.; Kindl, M.; Fernández, E. C.

    2013-12-01

    Specimens prepared from yacon roots in first two weeks after harvest were tested by dynamic mechanical analysis thermal analysis at temperatures between 30 and 90°C. No differences between different parts of roots were proved. There were indicated some differences in the test parameters that were caused by short time storage of the roots. One source of the differences was loss of water during the roots storage. The measured modulus increased during short time storage. Detailed study of changes of the modulus during the specimen dynamic mechanical analysis test provided information about different development of the storage and loss moduli during the specimen heating. The observed results can be caused by changes in cellular membranes observed earlier during vegetable heating, and by composition changes due to less stable components of yacon like inulin.

  11. Tree root systems and nutrient mobilization

    DEFF Research Database (Denmark)

    Boyle, Jim; Rob, Harrison; Raulund-Rasmussen, Karsten

    Roots mobilize nutrients via deep penetration and rhizosphere processes inducing weathering of primary minerals. These contribute to C transfer to soils and to tree nutrition. Assessments of these characteristics and processes of root systems are important for understanding long-term supplies...... some of the world’s most productive intensively managed forests, including Brazil and the Southeast and Pacifi c Northwest regions of the United States, have shown that root systems are often several meters in depth, and often extend deeper than soil is sampled. Large amounts of carbon are also...... sometimes stored at depth. Other recent studies on potential release of nutrients due to chemical weathering indicate the importance of root access to deep soil layers. Release profi les clearly indicate depletion in the top layers and a much higher potential in B and C horizons. Review of evaluations...

  12. BGP reflection functors in root categories

    Institute of Scientific and Technical Information of China (English)

    XIAO Jie; ZHANG Guanglian; ZHU Bin

    2005-01-01

    We define the BGP-reflection functors in the derived categories and the root categories. By Ringel's Hall algebra approach, the BGP-reflection functor is applicable to obtain the classical Weyl group action on the Lie algebra.

  13. Tooth mobility changes subsequent to root fractures

    DEFF Research Database (Denmark)

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

    2012-01-01

    of pulp necrosis in the coronal fragment. Furthermore, the effect of age, location of the fracture on the root, and observation period on mobility values was analyzed. Mobility values were measured for 44 of 95 previous reported root-fractured permanent incisors. Mobility changes were measured......The purpose of this study was to analyze tooth mobility changes in root-fractured permanent teeth and relate this to type of interfragment healing (hard tissue healing (HT), interfragment healing with periodontal ligament (PDL) and nonhealing with interposition of granulation tissue (GT) because...... after 3 months and 1 year, and a normalization of mobility value was usually found after 5 and 10 years. In 17 cases of PDL healing, generally a higher mobility was found in comparison with root fractures healing with hard tissue, and a consistent decrease in mobility value was found in the course...

  14. Naine objektistab meest / Fideelia-Signe Roots

    Index Scriptorium Estoniae

    Roots, Fideelia-Signe, 1976-

    2009-01-01

    Fideelia-Signe Roots Eesti Kunstiakadeemias 2009. a. kevadsemestril enda poolt läbi viidud valikainekursusest "Kunstiteose anatoomiast mehe anatoomiani", mis lõppes näitusega "Tõuseb / ei tõuse" Eesti Tervishoiumuuseumis, avatud 31. maini

  15. Elements with Square Roots in Finite Groups

    Institute of Scientific and Technical Information of China (English)

    M.S. Lucido; M.R. Pournaki

    2005-01-01

    In this paper, we study the probability that a randomly chosen element in a finite group has a square root, in particular the simple groups of Lie type of rank 1, the sporadic finite simple groups and the alternating groups.

  16. Dechlorodauricumine from cultured roots of Menispermum dauricum.

    Science.gov (United States)

    Sugimoto, Yukihiro; Matsui, Miharu; Takikawa, Hirosato; Sasaki, Mitsuru; Kato, Masako

    2005-11-01

    Dechlorodauricumine, a possible organic substrate for biochlorination, was isolated from cultured roots of Menispermum dauricum, a rich source of chlorinated alkaloids. Its structure was established by spectroscopic and chemical methods.

  17. ROOT I/O in Javascript - Reading ROOT files in a browser

    CERN Document Server

    CERN. Geneva

    2012-01-01

    A JavaScript version of the ROOT I/O subsystem is being developed, in order to be able to browse (inspect) ROOT files in a platform independent way. This allows the content of ROOT files to be displayed in most web browsers, without having to install ROOT or any other software on the server or on the client. This gives a direct access to ROOT files from new (e.g. portable) devices in a light way. It will be possible to display simple graphical objects such as histograms and graphs (TH1, TH2, TH3, TProfile, TGraph, ...). The rendering will first be done with an external JavaScript graphic library, before investigating a way to produce graphics closer to what ROOT supports on other platforms (X11, Windows).

  18. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Dutch researchers from the TN0 Institute have developed a technique to carry out gas-liquid contacting operations using hollow fibre membranes in combination with an absorption liquid. The method known as membrane gas absorption, aims to combine the advantages of membrane technology (compactness, fl

  19. Flattening, generalizations of clauses and absorption algorithms

    NARCIS (Netherlands)

    S-H. Nienhuys-Cheng (Shan-Hwei)

    1991-01-01

    textabstractIn predicate logic, flattening can be used to replace terms with functions by variables. It can also be used for expressing absorption in inverse resolution. This has been done by Rouveirol and Puget. In this article three kinds of absorption algorithms are compared.

  20. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption is a new, efficient and flexible way to carry out gas-liquid contacting operations with hollow fibre membranes. Advantages of gas absorption membranes over conventional G-L contactors are: -High specific surface area and rapid mass transfer resulting in very compact and low w

  1. Iron absorption from intrinsically-labeled lentils

    Science.gov (United States)

    Low iron (Fe) absorption from important staple foods may contribute to Fe deficiency in developing countries. To date, there are few studies examining the Fe bioavailability of pulse crops as commonly prepared and consumed by humans. The objectives of this study were to characterize the Fe absorpt...

  2. Oligofructose stimulates calcium absorption in adolescents

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muys, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Background: In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects. Objective: The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents. Design: Tw

  3. Cavity-enhanced absorption for optical refrigeration

    CERN Document Server

    Seletskiy, Denis V; Sheik-Bahae, Mansoor

    2009-01-01

    A 20-fold increase over the single path optical absorption is demonstrated with a low loss medium placed in a resonant cavity. This has been applied to laser cooling of Yb:ZBLAN glass resulting in 90% absorption of the incident pump light. A coupled-cavity scheme to achieve active optical impedance matching is analyzed.

  4. Determination of spectrophotometric absorptivity by analytical ultracentrifugation

    Directory of Open Access Journals (Sweden)

    M Senthilraja

    2011-01-01

    Full Text Available Rapid determination of the absorptivity for a recombinant IgG monoclonal antibody using the Beckman equipped with both Raleigh interference and UV absorbance optical systems. The analytical ultracentrifuge data for determining spectrophotometric absorptivities is compared to experimental data from quantitative amino acid analysis and an enzymatic digestion method.

  5. Low absorptance porcelain-on-aluminum coating

    Science.gov (United States)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  6. Enriching Absorptive Capacity through Social Interaction

    NARCIS (Netherlands)

    Hotho, Jasper J.; Becker-Ritterspach, Florian; Saka-Helmhout, Ayse

    2012-01-01

    Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within multinational enterprises. But how individual behaviour translates into absorptive capacity at the subsidiary level, and how this is contingent on subsidiaries' social context, remains under-addressed. Th

  7. Morphology of Southern Hemisphere Riometer Auroral Absorption

    Science.gov (United States)

    2006-06-01

    range of frequencies used an inverse -square frequency dependence approximately holds. Morphology of Southern Hemisphere Riometer Auroral Absorption...Tecnológico under Proyecto No 1940934. Annex The percentage probability, QA, that an absorption A dB is exceed, is given as: Where Am is

  8. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  9. Absorption, bioavailability and metabolism of flavonoids

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2004-01-01

    To unravel mechanisms of action of dietary flavonoids in their potential role in disease prevention, it is crucial to know the factors that determine their release from foods, their extent of absorption, and their fate in the organism. Research on absorption, metabolism, and bioavailability of flavo

  10. Time dependent effects of two absorption enhancers on the nasal absorption of growth hormone in rabbits

    DEFF Research Database (Denmark)

    Vermehren, C.; Hansen, Harald S.; Thomsen, M.K.

    1996-01-01

    Enhancer-based drug preparations allow absorption of peptide drugs. We investigated the reversibility with time of nasal absorption of human growth hormone (hGH) induced by the absorption enhancers didecanoylphosphatidylcholine (DDPC) and a-cyclodextrin (a-CD). Rabbits were dosed intranasally wit...

  11. Effect of coupling between linear absorption and nonlinear absorption on Z-scan measurements

    Institute of Scientific and Technical Information of China (English)

    Zang Wei-Ping; Tian Jian-Guo; Liu Zhi-Bo; Zhou Wen-Yuan; Song Feng; Zhang Chun-Ping

    2005-01-01

    The contribution of multiphoton absorption to open-aperture Z-scan measurements is analysed by coordinate transformation.The approximate closed-form solution is obtained, which is suitable for application in higher-optical power regime.as nad example, the coupling between linear absorption and two-photon absorption is discussed in detail.

  12. Development of TRatioPlot in ROOT

    CERN Document Server

    Gessinger-Befurt, Paul

    2016-01-01

    The ROOT data analysis and visualization framework is a software package which is widely used in physics, especially in high energy physics. A common visualization which has so far been lacking a direct implementation is the ratio plot, as well as a few similar types of plots. The scope and goal of the summer student project at CERN was to implement a class in ROOT itself, that can take care of the most common types of calculations, and produces high quality visuals.

  13. Sparse DOA estimation with polynomial rooting

    OpenAIRE

    Xenaki, Angeliki; Gerstoft, Peter; Fernandez Grande, Efren

    2015-01-01

    Direction-of-arrival (DOA) estimation involves the localization of a few sources from a limited number of observations on an array of sensors. Thus, DOA estimation can be formulated as a sparse signal reconstruction problem and solved efficiently with compressive sensing (CS) to achieve highresolution imaging. Utilizing the dual optimal variables of the CS optimization problem, it is shown with Monte Carlo simulations that the DOAs are accurately reconstructed through polynomial rooting (Root...

  14. Rational Convolution Roots of Isobaric Polynomials

    OpenAIRE

    Conci, Aura; Li, Huilan; MacHenry, Trueman

    2014-01-01

    In this paper, we exhibit two matrix representations of the rational roots of generalized Fibonacci polynomials (GFPs) under convolution product, in terms of determinants and permanents, respectively. The underlying root formulas for GFPs and for weighted isobaric polynomials (WIPs), which appeared in an earlier paper by MacHenry and Tudose, make use of two types of operators. These operators are derived from the generating functions for Stirling numbers of the first kind and second kind. Hen...

  15. Operating protocols of external root cervical resorption

    OpenAIRE

    Luca Venuti

    2015-01-01

    Aim: Theme of this report is the external cervical root resorption and the sequence of clinical procedures to be implemented during the phases of treatment. The external cervical root resorption (ICR) presents particular pathological conditions such as to classify between resorption of inflammatory origin.1–3 It is generally presented as a complex clinical situation both in the diagnosis in a predictable prognosis.3–6 It's often associated with loss of calcified tissue: dentin, cementum, a...

  16. Development of Machine Learning Tools in ROOT

    Science.gov (United States)

    Gleyzer, S. V.; Moneta, L.; Zapata, Omar A.

    2016-10-01

    ROOT is a framework for large-scale data analysis that provides basic and advanced statistical methods used by the LHC experiments. These include machine learning algorithms from the ROOT-integrated Toolkit for Multivariate Analysis (TMVA). We present several recent developments in TMVA, including a new modular design, new algorithms for variable importance and cross-validation, interfaces to other machine-learning software packages and integration of TMVA with Jupyter, making it accessible with a browser.

  17. Two root canals in maxillary central incisor

    Directory of Open Access Journals (Sweden)

    Fábio de Almeida Gomes

    2011-07-01

    Full Text Available Introduction and objective: The success of endodontic treatment requires the knowledge of tooth morphology and its variations. Case report: This clinical article reports an unusual root canal configuration that was detected in a maxillary central incisor with two root canals, demonstrated by radiographic and computerized tomography exams. Conclusion: Knowledge of endodontic anatomy as well as the obtainment of both preoperative radiographs and tomography is important to detect abnormal tooth morphology.

  18. Interspecific coordination and intraspecific plasticity of fine root traits in North American temperate tree species

    Directory of Open Access Journals (Sweden)

    Cornelia Marie Tobner

    2013-07-01

    Full Text Available Fine roots play an important role in nutrient and water absorption and hence overall tree performance. However, current understanding of the ecological role of belowground traits lags considerably behind those of aboveground traits. In this study, we used data on specific root length (SRL, fine root diameter (D and branching intensity (BI of two datasets to examine interspecific trait coordination as well as intraspecific trait variation across ontogenetic stage and soil conditions (i.e. plasticity. The first dataset included saplings of twelve North American temperate tree species grown in monocultures in a common garden experiment to examine interspecific trait coordination. The second dataset included adult and juvenile individuals of four species (present in both datasets co-occurring in natural forests on contrasting soils (i.e. humid organic, mesic and xeric podzolic. The three fine root traits investigated were strongly coordinated, with high SRL being related to low D and high BI. Fine root traits and aboveground life-strategies (i.e. relative growth rate were weakly coordinated and never significant. Intraspecific responses to changes in ontogenetic stage or soil conditions were trait dependent. SRL was significantly higher in juveniles compared to adults for A. balsamea and A. rubrum, but did not vary with soil condition. BI did not vary significantly with either ontogeny or soil conditions, while D was generally significantly lower in juveniles and higher in humid organic soils. D also had the least total (natural variation most of which was due to changes in the environment (plasticity. This study brings support for the emerging evidence for interspecific root trait coordination in trees. It also indicates that intraspecific responses to both ontogeny and soil conditions are trait dependent and less concerted. D appears to be a better indicator of environmental change than SRL and BI.

  19. Relationships between root respiration rate and root morphology, chemistry and anatomy in Larix gmelinii and Fraxinus mandshurica.

    Science.gov (United States)

    Jia, Shuxia; McLaughlin, Neil B; Gu, Jiacun; Li, Xingpeng; Wang, Zhengquan

    2013-06-01

    Tree roots are highly heterogeneous in form and function. Previous studies revealed that fine root respiration was related to root morphology, tissue nitrogen (N) concentration and temperature, and varied with both soil depth and season. The underlying mechanisms governing the relationship between root respiration and root morphology, chemistry and anatomy along the root branch order have not been addressed. Here, we examined these relationships of the first- to fifth-order roots for near surface roots (0-10 cm) of 22-year-old larch (Larix gmelinii L.) and ash (Fraxinus mandshurica L.) plantations. Root respiration rate at 18 °C was measured by gas phase O2 electrodes across the first five branching order roots (the distal roots numbered as first order) at three times of the year. Root parameters of root diameter, specific root length (SRL), tissue N concentration, total non-structural carbohydrates (starch and soluble sugar) concentration (TNC), cortical thickness and stele diameter were also measured concurrently. With increasing root order, root diameter, TNC and the ratio of root TNC to tissue N concentration increased, while the SRL, tissue N concentration and cortical proportion decreased. Root respiration rate also monotonically decreased with increasing root order in both species. Cortical tissue (including exodermis, cortical parenchyma and endodermis) was present in the first three order roots, and cross sections of the cortex for the first-order root accounted for 68% (larch) and 86% (ash) of the total cross section of the root. Root respiration was closely related to root traits such as diameter, SRL, tissue N concentration, root TNC : tissue N ratio and stele-to-root diameter proportion among the first five orders, which explained up to 81-94% of variation in the rate of root respiration for larch and up to 83-93% for ash. These results suggest that the systematic variations of root respiration rate within tree fine root system are possibly due to the

  20. Acid protease production in fungal root endophytes.

    Science.gov (United States)

    Mayerhofer, Michael S; Fraser, Erica; Kernaghan, Gavin

    2015-01-01

    Fungal endophytes are ubiquitous in healthy root tissue, but little is known about their ecosystem functions, including their ability to utilize organic nutrient sources such as proteins. Root-associated fungi may secrete proteases to access the carbon and mineral nutrients within proteins in the soil or in the cells of their plant host. We compared the protein utilization patterns of multiple isolates of the root endophytes Phialocephala fortinii s.l., Meliniomyces variabilis and Umbelopsis isabellina with those of two ectomycorrhizal (ECM) fungi, Hebeloma incarnatulum and Laccaria bicolor, and the wood-decay fungus Irpex lacteus at pH values of 2-9 on liquid BSA media. We also assessed protease activity using a fluorescently labeled casein assay and gelatin zymography and characterized proteases using specific protease inhibitors. I. lacteus and U. isabellina utilized protein efficiently, while the ECM fungi exhibited poor protein utilization. ECM fungi secreted metallo-proteases and had pH optima above 4, while other fungi produced aspartic proteases with lower pH optima. The ascomycetous root endophytes M. variabilis and P. fortinii exhibited intermediate levels of protein utilization and M. variabilis exhibited a very low pH optimum. Comparing proteolytic profiles between fungal root endophytes and fungi with well defined ecological roles provides insight into the ecology of these cryptic root associates.

  1. Extracellular DNA: the tip of root defenses?

    Science.gov (United States)

    Hawes, Martha C; Curlango-Rivera, Gilberto; Wen, Fushi; White, Gerard J; Vanetten, Hans D; Xiong, Zhongguo

    2011-06-01

    This review discusses how extracellular DNA (exDNA) might function in plant defense, and at what level(s) of innate immunity this process might operate. A new role for extracellular factors in mammalian defense has been described in a series of studies. These studies reveal that cells including neutrophils, eosinophils, and mast cells produce 'extracellular traps' (ETs) consisting of histone-linked exDNA. When pathogens are attracted to such ETs, they are trapped and killed. When the exDNA component of ETs is degraded, trapping is impaired and resistance against invasion is reduced. Conversely, mutation of microbial genes encoding exDNases that degrade exDNA results in loss of virulence. This discovery that exDNases are virulence factors opens new avenues for disease control. In plants, exDNA is required for defense of the root tip. Innate immunity-related proteins are among a group of >100 proteins secreted from the root cap and root border cell populations. Direct tests revealed that exDNA also is rapidly synthesized and exported from the root tip. When this exDNA is degraded by the endonuclease DNase 1, root tip resistance to fungal infection is lost; when the polymeric structure is degraded more slowly, by the exonuclease BAL31, loss of resistance to fungal infection is delayed accordingly. The results suggest that root border cells may function in a manner analogous to that which occurs in mammalian cells.

  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. Roots of Dehn twists about separating curves

    CERN Document Server

    Rajeevsarathy, Kashyap

    2011-01-01

    Let $C$ be a curve in a closed orientable surface $F$ of genus $g \\geq 2$ that separates $F$ into subsurfaces $\\widetilde {F_i}$ of genera $g_i$, for $i = 1,2$. We study the set of roots in $\\Mod(F)$ of the Dehn twist $t_C$ about $C$. All roots arise from pairs of $C_{n_i}$-actions on the $\\widetilde{F_i}$, where $n=\\lcm(n_1,n_2)$ is the degree of the root, that satisfy a certain compatibility condition. The $C_{n_i}$ actions are of a kind that we call nestled actions, and we classify them using tuples that we call data sets. The compatibility condition can be expressed by a simple formula, allowing a classification of all roots of $t_C$ by compatible pairs of data sets. We use these data set pairs to classify all roots for $g = 2$ and $g = 3$. We show that there is always a root of degree at least $2g^2+2g$, while $n \\leq 4g^2+2g$. We also give some additional applications.

  4. Gene expression regulation in roots under drought.

    Science.gov (United States)

    Janiak, Agnieszka; Kwaśniewski, Mirosław; Szarejko, Iwona

    2016-02-01

    Stress signalling and regulatory networks controlling expression of target genes are the basis of plant response to drought. Roots are the first organs exposed to water deficiency in the soil and are the place of drought sensing. Signalling cascades transfer chemical signals toward the shoot and initiate molecular responses that lead to the biochemical and morphological changes that allow plants to be protected against water loss and to tolerate stress conditions. Here, we present an overview of signalling network and gene expression regulation pathways that are actively induced in roots under drought stress. In particular, the role of several transcription factor (TF) families, including DREB, AP2/ERF, NAC, bZIP, MYC, CAMTA, Alfin-like and Q-type ZFP, in the regulation of root response to drought are highlighted. The information provided includes available data on mutual interactions between these TFs together with their regulation by plant hormones and other signalling molecules. The most significant downstream target genes and molecular processes that are controlled by the regulatory factors are given. These data are also coupled with information about the influence of the described regulatory networks on root traits and root development which may translate to enhanced drought tolerance. This is the first literature survey demonstrating the gene expression regulatory machinery that is induced by drought stress, presented from the perspective of roots.

  5. Defining the core Arabidopsis thaliana root microbiome

    Science.gov (United States)

    Gehring, Jase; Malfatti, Stephanie; Tremblay, Julien; Engelbrektson, Anna; Kunin, Victor; del Rio, Tijana Glavina; Edgar, Robert C.; Eickhorst, Thilo; Ley, Ruth E.; Hugenholtz, Philip; Tringe, Susannah Green; Dangl, Jeffery L.

    2014-01-01

    Land plants associate with a root microbiota distinct from the complex microbial community present in surrounding soil. The microbiota colonizing therhizosphere(immediately surroundingthe root) and the endophytic compartment (within the root) contribute to plant growth, productivity, carbon sequestration and phytoremediation1-3. Colonization of the root occurs despite a sophisticated plant immune system4,5, suggesting finely tuned discrimination of mutualists and commensals from pathogens. Genetic principles governing the derivation of host-specific endophyte communities from soil communities are poorly understood. Here we report the pyrosequencing of the bacterial 16S ribosomal RNA gene of more than 600 Arabidopsis thaliana plants to test the hypotheses that the root rhizosphere and endophytic compartment microbiota of plants grown under controlled conditions in natural soils are sufficiently dependent on the host to remain consistent across different soil types and developmental stages, and sufficiently dependent on host genotype to vary between inbred Arabidopsis accessions. We describe different bacterial communities in two geochemically distinct bulk soils and in rhizosphere and endophytic compartments prepared from roots grown in these soils. The communities in each compartment are strongly influenced by soil type. Endophytic compartments from both soils feature overlapping, low-complexity communities that are markedly enriched in Actinobacteria and specific families from other phyla, notably Proteobacteria. Some bacteria vary quantitatively between plants of different developmental stage and genotype. Our rigorous definition of an endophytic compartment microbiome should facilitate controlled dissection of plantmicrobe interactions derived from complex soil communities. PMID:22859206

  6. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  7. Absorption imaging of a single atom

    Science.gov (United States)

    Streed, Erik W.; Jechow, Andreas; Norton, Benjamin G.; Kielpinski, David

    2012-07-01

    Absorption imaging has played a key role in the advancement of science from van Leeuwenhoek's discovery of red blood cells to modern observations of dust clouds in stellar nebulas and Bose-Einstein condensates. Here we show the first absorption imaging of a single atom isolated in a vacuum. The optical properties of atoms are thoroughly understood, so a single atom is an ideal system for testing the limits of absorption imaging. A single atomic ion was confined in an RF Paul trap and the absorption imaged at near wavelength resolution with a phase Fresnel lens. The observed image contrast of 3.1 (3)% is the maximum theoretically allowed for the imaging resolution of our set-up. The absorption of photons by single atoms is of immediate interest for quantum information processing. Our results also point out new opportunities in imaging of light-sensitive samples both in the optical and X-ray regimes.

  8. [Effect of altitude on iron absorption].

    Science.gov (United States)

    Pizarro, F; Zavaleta, N; Hertrampf, E; Berlanga, R; Camborda, L; Olivares, M

    1998-03-01

    Iron bioavailability was evaluated in people living in high altitudes. Absorption was estimated from a reference dose of ferrous ascorbate and from a standard diet of wheat flour, using extrinsic tag radioisotope technique of 55Fe and 59Fe. Twenty four volunteers, healthy women, with ages ranging from 28 to 45 years, participated. Of those, eleven lived at 3450 meters above sea level (m.a.s.l.) in Huancayo city-Peru (study group), and 13 lived in Santiago de Chile at 630 m.a.s.l. (control group). Iron absorption from reference dose of ferrous ascorbate was 32.0% and 31.1% in the study and control groups respectively. The geometric mean of iron absorption from the standard diet, corrected to 40% of absorption of reference dose, was 9.0% and 6.9% in the study and control groups respectively (NS). The results suggest that altitude does not produce a high iron absorption in highlander residents.

  9. Short-term tissue response to potential root-end filling materials in infected root canals.

    Science.gov (United States)

    Chong, B S; Pitt Ford, T R; Kariyawasam, S P

    1997-07-01

    The short-term tissue responses to two potential root-end filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol), were compared with that to amalgam using a previously devised experimental model. In 24 premolar teeth of beagle dogs (47 roots), a collection of endodontic pathogenic bacteria was first inoculated into the root canals to induce periradicular lesions. On each root, an apicoectomy was performed and root-end cavities prepared to receive fillings of each material. The teeth and surrounding jaw were removed after 2 weeks (23 roots) and 1 week (24 roots); they were then prepared for histological examination. The tissue response to amalgam fillings after 2 weeks and 1 week was marked by moderate or severe inflammation on all roots, and extended to 0.5 mm in 15 out of 16 roots. In contrast, after 2 weeks, the majority of roots filled with Kalzinol showed little or moderate inflammation, while the tissue response to Vitrebond was the best of the three materials, and was also the least extensive. After 1 week, the overall best tissue response was with Vitrebond, followed by Kalzinol. The differences between materials for both time periods with either none or few inflammatory cells when compared with that with either moderate or severe inflammation were not statistically significant (P inflammation or inflammation extending inflammation extending > 0.2 mm ( 0.5 mm) were statistically significant (P inflammation adjacent to the root-end filling, even though there were intersample variations, there was little overall difference in the temporal and qualitative healing response to Vitrebond and Kalzinol. Both Vitrebond and Kalzinol have potential as root-end filling materials, as the tissue response was considerably more favourable than that to amalgam even in the short-term.

  10. Impact of salt stress on the features and activities of root system for three desert halophyte species in their seedling stage

    Institute of Scientific and Technical Information of China (English)

    YI LiangPeng; MA Jian; LI Yan

    2007-01-01

    Linkage between belowground and aboveground sections of ecological system is mainly depending on root system. But root system is the parts of plant that people less understand. The absorption function of root system is closely related to their morphology and activity. Moreover root system can interact with the environmental stress under the adverse situation, and adjust its system to take adaptation responses in morphology and physiology to strengthen its survival chance. This research is focused on three desert halophyte species of H. ammodendron (C.A.Mey.) Bge., S. physophora Pall., and S.nitraria Pall. under solution culture, to study the differences of their root system morphology and activity in the seedling stage under varying salt concentration conditions. The study results show that: A certain salt concentration can promote development of these three halophytes; but rather high salt concentration will restrain their growth, in particular inhibit the root system development. Under the same salt concentration condition, S. nitraria Pall. grows fast and accumulates the largest amount of biomass. Under relatively low salt concentration, the length of axial root and the total length of root system of these three halophyte species are all increased; and compared to the checking samples, S.physophora Pall. occupies the top place of root system growth, but the high salt concentration will restrain the increase of total root length; among them, the impact intensity on S. physophora Pall. is lighter than to H. ammodendron (C.A.Mey.) Bge. and S. nitraria Pall. is lighter; the salinity does not bring distinct influence on the average diameter of root system of these three plant species, but trends to reducing the size; under the solution culture conditions, the middle and lower parts of the axial root of H. ammodendron (C.A.Mey.) Bge. and S. physophora Pall. are rather equally distributed, but the central zone of S. nitraria Pall. root system is more significantly

  11. Absorption-Line Studies of Seyfert Galaxies

    Science.gov (United States)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  12. New insights to lateral rooting: Differential responses to heterogeneous nitrogen availability among maize root types.

    Science.gov (United States)

    Yu, Peng; White, Philip J; Li, Chunjian

    2015-01-01

    Historical domestication and the "Green revolution" have both contributed to the evolution of modern, high-performance crops. Together with increased irrigation and application of chemical fertilizers, these efforts have generated sufficient food for the growing global population. Root architecture, and in particular root branching, plays an important role in the acquisition of water and nutrients, plant performance, and crop yield. Better understanding of root growth and responses to the belowground environment could contribute to overcoming the challenges faced by agriculture today. Manipulating the abilities of crop root systems to explore and exploit the soil environment could enable plants to make the most of soil resources, increase stress tolerance and improve grain yields, while simultaneously reducing environmental degradation. In this article it is noted that the control of root branching, and the responses of root architecture to nitrate availability, differ between root types and between plant species. Since the control of root branching depends upon both plant species and root type, further work is urgently required to determine the appropriate genes to manipulate to improve resource acquisition by specific crops.

  13. Enhanced MRI in compressed lumbosacral nerve root; Alteration of vascular peameability in nerve root

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Tomofumi; Yoshizawa, Hidezo; Nakai, Sadaaki; Kobayashi, Shigeru; Hachiya, Hiromichi; Nakagawa, Masato; Nishimoto, Satoshi (Fujita Health Univ., Toyoake, Aichi (Japan). School of Medicine)

    1993-04-01

    The study was undertaken to assess how enhanced MRI reflects pathophysiology of the nerve root. In fundamental study, the seventh left lumbar nerve root was compressed by a clip for one hour in 10 mongrel dogs. Thirty min after removal of mechanical compression, gadolinium and Evans blue albumin (EBA) were iv injected. Then, the dogs were killed 10 min later. A mass of lumbosacral nerve root was removed for MR imaging. In addition, nerve root slices were prepared to examine changes in vascular permeability of EBA under microscopy. The compression area of nerve root was seen as hyperintensity on enhanced MRI, corresponding to extravascular leakage of EBA that resulted from the damaged blood-nerve barrier, i.e., edema within the root on microscope. In a clinical setting, 27 patients with lumbar disc herniation underwent MRI for the observation of the nerve root. In 8 of these 27 patients, the nerve root was seen as hyperintensity. This suggests that approximately one third of such patients may have edema within the nerve root. (N.K.).

  14. Capturing Arabidopsis root architecture dynamics with ROOT-FIT reveals diversity in responses to salinity.

    Science.gov (United States)

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

    2014-11-01

    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.

  15. Root caries, root surface restorations and lifestyle factors in adult Danes

    DEFF Research Database (Denmark)

    Christensen, Lisa Bøge; Jensen, Allan Bardow; Ekstrand, Kim

    2015-01-01

    AIM: To investigate selected lifestyle factors in relation to active caries and restored root surface lesions in adults. MATERIALS AND METHODS: Based on clinical examinations and questionnaires, data on root caries, socioeconomic status, body mass index, dietary habits, alcohol consumption, tobacco...... dentures were significantly associated with presence of active root caries (p tobacco use and alcohol...... consumption, as well as wearing dentures, were significantly associated with the occurrence of untreated caries and restored root surface lesions, especially in persons over 45. Thus, such lifestyle factors should be taken into consideration, identifying persons with a need of preventive dental services...

  16. Root cortical senescence decreases root respiration, nutrient content, and radial water and nutrient transport in barley.

    Science.gov (United States)

    Schneider, Hannah M; Wojciechowski, Tobias; Postma, Johannes A; Brown, Kathleen M; Lücke, Andreas; Zeisler, Viktoria; Schreiber, Lukas; Lynch, Jonathan P

    2017-02-06

    The functional implications of root cortical senescence (RCS) are poorly understood. We tested the hypotheses that RCS in barley: (1) reduces the respiration and nutrient content of root tissue; (2) decreases radial water and nutrient transport; (3) is accompanied by increased suberization to protect the stele. Genetic variation for RCS exists between modern germplasm and landraces. Nitrogen and phosphorus deficiency increased the rate of RCS. Maximal RCS, defined as the disappearance of the entire root cortex, reduced root nitrogen content by 66%, phosphorus content by 63%, and respiration by 87% compared to root segments with no RCS. Roots with maximal RCS had 90%, 92%, and 84% less radial water, nitrate, and phosphorus transport, respectively compared to segments with no RCS. The onset of RCS coincided with 30% greater aliphatic suberin in the endodermis. These results support the hypothesis that RCS reduces root carbon and nutrient costs and may therefore have adaptive significance for soil resource acquisition. By reducing root respiration and nutrient content, RCS could permit greater root growth, soil resource acquisition, and resource allocation to other plant processes. RCS merits investigation as a trait for improving the performance of barley, wheat, triticale, and rye under edaphic stress.

  17. Plant root tortuosity: an indicator of root path formation in soil with different composition and density

    Science.gov (United States)

    Popova, Liyana; van Dusschoten, Dagmar; Nagel, Kerstin A.; Fiorani, Fabio; Mazzolai, Barbara

    2016-01-01

    Background and Aims Root soil penetration and path optimization are fundamental for root development in soil. We describe the influence of soil strength on root elongation rate and diameter, response to gravity, and root-structure tortuosity, estimated by average curvature of primary maize roots. Methods Soils with different densities (1·5, 1·6, 1·7 g cm−3), particle sizes (sandy loam; coarse sand mixed with sandy loam) and layering (monolayer, bilayer) were used. In total, five treatments were performed: Mix_low with mixed sand low density (three pots, 12 plants), Mix_medium - mixed sand medium density (three pots, 12 plants), Mix_high - mixed sand high density (three pots, ten plants), Loam_low sandy loam soil low density (four pots, 16 plants), and Bilayer with top layer of sandy loam and bottom layer mixed sand both of low density (four pots, 16 plants). We used non-invasive three-dimensional magnetic resonance imaging to quantify effects of these treatments. Key Results Roots grew more slowly [root growth rate (mm h–1); decreased 50 %] with increased diameters [root diameter (mm); increased 15 %] in denser soils (1·7 vs. 1·5 g cm–3). Root response to gravity decreased 23 % with increased soil compaction, and tortuosity increased 10 % in mixed sand. Response to gravity increased 39 % and tortuosity decreased 3 % in sandy loam. After crossing a bilayered–soil interface, roots grew more slowly, similar to roots grown in soil with a bulk density of 1·64 g cm–3, whereas the actual experimental density was 1·48±0·02 g cm–3. Elongation rate and tortuosity were higher in Mix_low than in Loam_low. Conclusions The present study increases our existing knowledge of the influence of physical soil properties on root growth and presents new assays for studying root growth dynamics in non-transparent media. We found that root tortuosity is indicative of root path selection, because it could result from both mechanical deflection and

  18. A new Approach for Quantifying Root-Reinforcement of Streambanks: the RipRoot Model

    Science.gov (United States)

    Pollen, N. L.; Simon, A.

    2003-12-01

    Riparian vegetation plays an important role in controlling geotechnical and fluvial processes acting along and within streambanks through the binding effects of roots. Quantification of this mechanical effect is therefore essential to accurately model streambank stability. Until now, most attempts to include the effects of root reinforcement by riparian vegetation have used root-cohesion values estimated using the Wu et al. (1979) equation, requiring the tensile strengths and diameters of the roots crossing the potential shear-plane. However, the Wu et al. equation is a static model that assumes that all roots break, and that they all break simultaneously. Field observations and laboratory experiments have shown that in reality the roots do not all break simultaneously, and that the breaking of roots during mass failure is in fact a dynamic process. Static models such as the Wu et al. equation are therefore likely to produce overestimations of cohesion due to roots. As a response to this concern, a dynamic root reinforcement model (RipRoot) was developed, based on the concepts of fiber bundle models (FBM's) used in materials science. Within the model the root-soil system is loaded incrementally resulting in progressive root breaking and redistribution of stresses from the broken roots to the remaining intact roots in the soil matrix. The redistribution and loading process continues until either all of the roots have broken, or equilibrium is reached where the root network supports the driving force imposed on the bank. The increase in bank cohesion using the static Wu et al. equation are 18% to 38% higher than RipRoot for riparian tree species, including Black Willow, Sandbar Willow, Cottonwood, River Birch and Eastern Sycamore, and 49% higher for Switch Grass. These variations in cohesion values can have a significant impact on streambank Factor of Safety (Fs) values calculated using the Simon et al. (2000) bank-stability model. For example, a 3m high silt

  19. The Effect of Humic Acid on Nutrient Composition in Broad Bean (Vicia faba L. Roots

    Directory of Open Access Journals (Sweden)

    Sener AKINCI

    2009-12-01

    Full Text Available Humic acids promote the conversion of mineral nutrients into forms available to plants. It also stimulates seed germination and viability, and its main effect usually being more prominent in the roots. The objective of this study was to determine of the influence of humic acid on broad bean (Vicia faba L. cultivar �Eresen 87� on root growth and development as well as nutrient uptake, during investigation in a pot experiment. Treatment with leonardite, as humic acid source positively affected both germination and harvesting, enhancing root length and biomass. Humic acid (HA caused significant increase of fresh (RFW and dry (RDW weights by 30.1% and 56.6% of broad bean roots, respectively. Flame photometer and atomic absorption spectrophotometry analyses revealed that K content was major nutrient among the tested elements. Humic acid increased the contents of Na and K significantly. The content of Ca and Fe was not significantly increased whereas Cu, Mn and Zn content decreased under HA treatment.

  20. Cr localization and speciation in roots of chromate fed Helianthus annuus L. seedlings using synchrotron techniques.

    Science.gov (United States)

    de la Rosa, Guadalupe; Castillo-Michel, Hiram; Cruz-Jiménez, Gustavo; Bernal-Alvarado, Jesús; Córdova-Fraga, Teodoro; López-Moreno, Laura; Cotte, Marine

    2014-01-01

    In order to gain knowledge on the potential use of Helianthus annuus L. for the remediation of Cr(VI) polluted waters, hydroponics experiments were set up to determine Cr uptake and tolerance in different Cr(VI)-sulfate conditions, and Cr biotransformations. Results indicated that Cr(VI) promoted seed germination, and plant tolerance was higher at younger plant stages. Cr uptake was dependent on sulfate concentrations. The highest Cr levels in roots and shoots (13,700 and 2,500 mg kg(-1) dry weight (DW), respectively) were obtained in 1 mM sulfate. The lowest Cr uptake in roots (10,600 mg kg(-1) DW) was observed in seedlings treated with no sulfate. In shoots, Cr concentration was of 1,500 mg kg(-1)DW for the 1 mM sulfate treatment, indicating a different level of interaction between chromate and sulfate in both tissues. For the first time, using micro X-ray florescence (muXRF), we demonstrated Cr reaches the root stele and is located in the walls of xylem vessels. Bulk and micro X-ray Absorption Near-Edge Structure (muXANES) results showed that Cr in the roots is mostly in the form of Cr(III) phosphate (80%), with the remainder complexed to organic acids. Our results suggest this plant species may serve for Cr(VI) rhizofiltration purposes.

  1. Microscopic biomineralization processes and Zn bioavailability: a synchrotron-based investigation of Pistacia lentiscus L. roots.

    Science.gov (United States)

    De Giudici, G; Medas, D; Meneghini, C; Casu, M A; Gianoncelli, A; Iadecola, A; Podda, S; Lattanzi, P

    2015-12-01

    Plants growing on polluted soils need to control the bioavailability of pollutants to reduce their toxicity. This study aims to reveal processes occurring at the soil-root interface of Pistacia lentiscus L. growing on the highly Zn-contaminated tailings of Campo Pisano mine (SW Sardinia, Italy), in order to shed light on possible mechanisms allowing for plant adaptation. The study combines conventional X-ray diffraction (XRD) and scanning electron microscopy (SEM) with advanced synchrotron-based techniques, micro-X-ray fluorescence mapping (μ-XRF) and X-ray absorption spectroscopy (XAS). Data analysis elucidates a mechanism used by P. lentiscus L. as response to high Zn concentration in soil. In particular, P. lentiscus roots take up Al, Si and Zn from the rhizosphere minerals in order to build biomineralizations that are part of survival strategy of the species, leading to formation of a Si-Al biomineralization coating the root epidermis. XAS analysis rules out Zn binding to organic molecules and indicates that Zn coordinates Si atoms stored in root epidermis leading to the precipitation of an amorphous Zn-silicate. These findings represent a step forward in understanding biological mechanisms and the resulting behaviour of minor and trace elements during plant-soil interaction and will have significant implications for development of phytoremediation techniques.

  2. Effect of Exponential Fertilization on Biomass Allocation,Photosynthesis and Root Morphology of Padus maackii Seedlings%指数施肥对斑叶稠李苗木生物量分配、光合作用及根系形态的影响

    Institute of Scientific and Technical Information of China (English)

    郝龙飞; 王庆成; 刘婷岩; 许丽娟

    2014-01-01

    Biomass allocation,photosynthesis and root morphology of Padus maackii one-year-old bare-root seedlings under constant fertilization ( CF ) , exponential fertilization ( EF ) , doubled exponential fertilization ( DEF ) and no fertilization (CK) regimes were investigated. 1) By the end of the growing season,the root/shoot ratio of seedlings under EF treatment was maximum,and was 6. 7%,14. 3%,23. 1% greater than that with CK,CF and DEF treatment ( P DEF>CF>CK. Seedling height and collar diameter of EF treatment was 16. 6% and 28. 1% higher than those of CK,respectively ( PEF >CF >DEF. The number of first-order lateral root of EF was 19,and more than that with CK,CF,DEF treatment (P0. 05) greater than that with CK,CF and DEF treatment,respectively. 5) Compared with OF treatment, average length of first-order roots ( absorptive roots ) under EF and DEF treatment was 15 . 8%,16 . 7% higher ( P 0 . 05 ) ,respectively; Specific root length of first-order root under EF and DEF treatment was 13. 9%,14. 7% longer than that with CF treatment (P >0. 05),respectively. The fifth-order root of EF treatment had greater average length,average diameter and specific root length compared with CF treatment. Exponential fertilization regimes effectively promoted photosynthetic rate and improved root morphology, meanwhile, increased biomass accumulation and nutrient absorption in P. maackii seedlings.

  3. Modelling water uptake efficiency of root systems

    Science.gov (United States)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  4. Involvement of nitrogen functional groups in high-affinity copper binding in tomato and wheat root apoplasts: spectroscopic and thermodynamic evidence.

    Science.gov (United States)

    Guigues, Stéphanie; Bravin, Matthieu N; Garnier, Cédric; Masion, Armand; Chevassus-Rosset, Claire; Cazevieille, Patrick; Doelsch, Emmanuel

    2016-03-01

    Carboxylic groups located in plant cell walls (CW) are generally considered to be the main copper binding sites in plant roots, despite the presence of other functional groups. The aim of this study was to investigate sites responsible for copper binding in root apoplasts, i.e. CW and outer surface of the plasma membrane (PM) continuum. Binding sites in root apoplasts were investigated by comparing isolated CW of a monocotyledon (Triticum aestivum L.) and dicotyledon (Solanum lycopersicum L.) crop with their respective whole roots. Copper speciation was examined by X-ray absorption (XAS) and (13)C-nuclear magnetic resonance spectroscopies while the affinity of ligands involved in copper binding was investigated by modeling copper sorption isotherms. Homogeneous speciation and binding of copper was found in wheat and tomato root apoplasts. Only Cu-N and Cu-O bonds were detected in wheat and tomato root apoplasts. Nitrogen/oxygen ligands were identified in slightly higher proportions (40-70%) than single oxygen ligands. Furthermore, low- and high-affinity binding sites contributed in an almost equivalent proportion to copper binding in root apoplasts. The high-affinity N functional groups embedded in root apoplasts participated in copper binding in the same magnitude than the low-affinity carboxylic groups.

  5. Improvement of cadmium uptake and accumulation in Sedum alfredii by endophytic bacteria Sphingomonas SaMR12: effects on plant growth and root exudates.

    Science.gov (United States)

    Chen, Bao; Zhang, Yibin; Rafiq, Muhammad Tariq; Khan, Kiran Yasmin; Pan, Fengshan; Yang, Xiaoe; Feng, Ying

    2014-12-01

    Inoculating endophytic bacteria was proven as a promising way to enhance phytoremediation. By a hydroponic experiment, the role of this study was to clarify the effects of inoculating endophytic bacterium Sphingomonas SaMR12 on phytoremediation, with special emphasis on changes of cadmium uptake, plant growth, root morphology, and organic acids secretion at different cadmium treated levels (0, 5, 50, and 100 μM). The results showed that SaMR12 inoculation improved the accumulation of cadmium as well as plant biomass, length of roots, number of root tips, and root surface area. Root secretion of oxalic, citric, and succinic acids was also increased after inoculated, which may alleviate the cadmium toxicity to plant or inhibit the rising trend of oxidative stress of plant. The major finding of this work suggested that in the root, SaMR12 improves cadmium bioavailability and absorption facility by increasing root-soil contact area and root organic acid secretion; and in the shoot, SaMR12 increases cadmium tolerance by alleviating oxidative stress of plant, so as to enhance the capability of cadmium extraction by plant.

  6. D-Root: a system for cultivating plants with the roots in darkness or under different light conditions.

    Science.gov (United States)

    Silva-Navas, Javier; Moreno-Risueno, Miguel A; Manzano, Concepción; Pallero-Baena, Mercedes; Navarro-Neila, Sara; Téllez-Robledo, Bárbara; Garcia-Mina, Jose M; Baigorri, Roberto; Gallego, Francisco Javier; del Pozo, Juan C

    2015-10-01

    In nature roots grow in the dark and away from light (negative phototropism). However, most current research in root biology has been carried out with the root system grown in the presence of light. Here, we have engineered a device, called Dark-Root (D-Root), to grow plants in vitro with the aerial part exposed to the normal light/dark photoperiod while the roots are in the dark or exposed to specific wavelengths or light intensities. D-Root provides an efficient system for cultivating a large number of seedlings and easily characterizing root architecture in the dark. At the morphological level, root illumination shortens root length and promotes early emergence of lateral roots, therefore inducing expansion of the root system. Surprisingly, root illumination also affects shoot development, including flowering time. Our analyses also show that root illumination alters the proper response to hormones or abiotic stress (e.g. salt or osmotic stress) and nutrient starvation, enhancing inhibition of root growth. In conclusion, D-Root provides a growing system closer to the natural one for assaying Arabidopsis plants, and therefore its use will contribute to a better understanding of the mechanisms involved in root development, hormonal signaling and stress responses.

  7. Tissue response to potential root-end filling materials in infected root canals.

    Science.gov (United States)

    Chong, B S; Ford, T R; Kariyawasam, S P

    1997-03-01

    The tissue responses to two potential root-end filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol) were compared with that to amalgam. In 27 premolar teeth of beagle dogs (54 roots), a collection of endodontic pathogenic bacteria was first inoculated into the root canals to induce periapical lesions. On each root, an apicectomy was performed and root-end cavities prepared to receive fillings of each material. The teeth and surrounding jaw were removed after 8 weeks (24 roots) and 4 weeks (30 roots); and they were prepared for histological examination. The tissue response to amalgam fillings after 4 and 8 weeks was marked by moderate or severe inflammation on all roots, and extended > 0.5 mm in 10 out of 18 roots. In contrast, after 8 weeks, the majority of roots filled with Kalzinol showed little or moderate inflammation while the tissue response to Vitrebond was the best of the three materials, and was also less extensive. After 4 weeks, the overall best tissue response was with Kalzinol, followed closely by Vitrebond. The differences between materials for both time periods with either none or few inflammatory cells when compared with that with either moderate or severe inflammation were statistically significant (P inflammation or inflammation extending inflammation extending > 0.2 mm ( 0.5 mm) were statistically significant (P < 0.01). Both Vitrebond and Kalzinol have potential as root-end filling materials as the tissue response was considerably more favourable than that to amalgam.

  8. How can science education foster students' rooting?

    Science.gov (United States)

    Østergaard, Edvin

    2015-06-01

    The question of how to foster rooting in science education points towards a double challenge; efforts to prevent (further) uprooting and efforts to promote rooting/re-rooting. Wolff-Michael Roth's paper discusses the uprooting/rooting pair of concepts, students' feeling of alienation and loss of fundamental sense of the earth as ground, and potential consequences for teaching science in a rooted manner. However, the argumentation raises a number of questions which I try to answer. My argumentation rests on Husserl's critique of science and the "ontological reversal", an ontological position where abstract models from science are considered as more real than the everyday reality itself, where abstract, often mathematical, models are taken to be the real causes behind everyday experiences. In this paper, measures towards an "ontological re-reversal" are discussed by drawing on experiences from phenomenon-based science education. I argue that perhaps the most direct and productive way of promoting rooting in science class is by intentionally cultivating the competencies of sensing and aesthetic experience. An aesthetic experience is defined as a precognitive, sensuous experience, an experience that is opened up for through sensuous perception. Conditions for rooting in science education is discussed against three challenges: Restoring the value of aesthetic experience, allowing time for open inquiry and coping with curriculum. Finally, I raise the question whether dimensions like "reality" or "nature" are self-evident for students. In the era of constructivism, with its focus on cognition and knowledge building, the inquiry process itself has become more important than the object of inquiry. I argue that as educators of science teachers we have to emphasize more explicitly "the nature of nature" as a field of exploration.

  9. Environment friendly route of iron oxide nanoparticles from Zingiber officinale (ginger) root extract

    Science.gov (United States)

    Xin Hui, Yau; Yi Peng, Teoh; Wei Wen, Liu; Zhong Xian, Ooi; Peck Loo, Kiew

    2016-11-01

    Iron oxide nanoparticles were prepared from the reaction between the Zingiber officinale (ginger) root extracts and ferric chloride solution at 50°C for 2 h in mild stirring condition. The synthesized powder forms of nanoparticles were further characterized by using UV-Vis spectroscopy and X-ray Diffraction spectrometry. UV-Vis analysis shows the absorption peak of iron oxide nanoparticles is appeared at 370 nm. The calculation of crystallite size from the XRD showed that the average particle size of iron oxide nanoparticles was 68.43 nm. Therefore, this eco-friendly technique is low cost and large scale nanoparticles synthesis to fulfill the demand of various applications.

  10. Ion Flux in Roots of Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook) under Aluminum Stress

    OpenAIRE

    2016-01-01

    Chinese fir is a tall, fast-growing species that is unique to southern China. In Chinese fir plantations, successive plantings have led to a decline in soil fertility, and aluminum toxicity is thought to be one of the main reasons for this decline. In this study, Non-invasive Micro-test Technology was used to study the effect of aluminum stress on the absorption of 4 different ions in the roots of the Chinese fir clone FS01. The results are as follows: with increased aluminum concentration an...

  11. Absorption spectroscopy of EBT model GAFCHROMIC film.

    Science.gov (United States)

    Devic, Slobodan; Tomic, Nada; Pang, Zhiyu; Seuntjens, Jan; Podgorsak, Ervin B; Soares, Christopher G

    2007-01-01

    The introduction of radiochromic films has solved some of the problems associated with conventional 2D radiation detectors. Their high spatial resolution, low energy dependence, and near-tissue equivalence make them ideal for measurement of dose distributions in radiation fields with high dose gradients. Precise knowledge of the absorption spectra of these detectors can help to develop more suitable optical densitometers and potentially extend the use of these films to other areas such as the measurement of the radiation beam spectral information. The goal of this study is to present results of absorption spectra measurements for the new GAFCHROMIC film, EBT type, exposed to 6 MV photon beam in the dose range from 0 to 6 Gy. Spectroscopic analysis reveals that in addition to the two main absorption peaks, centered at around 583 and 635 nm, the absorption spectrum in the spectral range from 350 to 800 nm contains six more absorption bands. Comparison of the absorption spectra reveals that previous HD-810, MD-55, as well as HS GAFCHROMIC film models, have nearly the same sensitive layer base material, whereas the new EBT model, GAFCHROMIC film has a different composition of its sensitive layer. We have found that the two most prominent absorption bands in EBT model radiochromic film do not change their central wavelength position with change in a dose deposited to the film samples.

  12. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Mexicano de Petroleo (IMP) and CENICA.

  13. Water dimer absorption of visible light

    Directory of Open Access Journals (Sweden)

    J. Hargrove

    2007-07-01

    Full Text Available Laboratory measurements of water vapor absorption using cavity ring-down spectroscopy revealed a broad absorption at 405 nm with a quadratic dependence on water monomer concentration, a similar absorption with a linear component at 532 nm, and only linear absorption at 570 nm in the vicinity of water monomer peaks. D2O absorption is weaker and linear at 405 nm. Van't Hoff plots constructed at 405.26 nm suggest that for dimerization, Keq=0.056±0.02 atm−1, ΔH°301 K=−16.6±2 kJ mol−1 and ΔS°301 K=−80±10 J mol−1 K−1. This transition peaks at 409.5 nm, could be attributed to the 8th overtone of water dimer and the 532 nm absorption to the 6th overtone. It is possible that some lower overtones previously searched for are less enhanced. These absorptions could increase water vapor feed back calculations leading to higher global temperature projections with currently projected greenhouse gas levels or greater cooling from greenhouse gas reductions.

  14. Lactose enhances mineral absorption in infancy.

    Science.gov (United States)

    Ziegler, E E; Fomon, S J

    1983-05-01

    To determine if lactose promotes the intestinal absorption of calcium and other minerals by infants, metabolic balance studies were performed with infants fed two formulas nearly identical in composition except for carbohydrate. One contained only lactose and the other contained sucrose and corn starch hydrolysate. Each of six normal infants had two balance studies performed with each formula in alternating sequence. When lactose was the carbohydrate, net absorption and net retention of calcium were significantly greater than when lactose was not present in the formula. Absorptions of magnesium and manganese were also significantly enhanced by lactose. Absorptions of copper and zinc were somewhat greater (not statistically significant) when lactose was present, whereas absorption of iron was not affected. Absorption of phosphorus was not different, but urinary excretion was less when the lactose containing formula was fed and, hence, net retention of phosphorus was significantly enhanced. These results confirm findings from animal studies and previous human studies and show that, in infants, lactose has a significant and sustained promoting effect on absorption of calcium and other minerals.

  15. 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...

  16. Root bacterial endophytes alter plant phenotype, but not physiology

    DEFF Research Database (Denmark)

    Henning, Jeremiah A.; Weston, David J.; Pelletier, Dale A.;

    2016-01-01

    (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf...

  17. Not-so-resonant, resonant absorption

    Science.gov (United States)

    Brunel, F.

    1987-07-01

    When an intense electromagnetic wave is incident obliquely on a sharply bounded overdense plasma, strong energy absorption can be accounted for by the electrons that are dragged into the vacuum and sent back into the plasma with velocities v~=vosc. This mechanism is more efficient than usual resonant absorption for vosc/ω>L, with L being the density gradient length. In the very high-intensity CO2-laser-target interaction, this mechanism may account for most of the energy absorption.

  18. Electric modulation of optical absorption in nanowires

    Science.gov (United States)

    Sakr, M. R.

    2016-11-01

    We have calculated the effect of an external electric field on the intersubband optical absorption of a nanowire subjected to a perpendicular magnetic field and Rashba effect. The absorption peaks due to optical transitions that are forbidden in the absence of the intersubband coupling experience strong amplitude modulation. This effect is quadratic in electric fields applied along the direction of quantum confinement or perpendicularly to tune the Rashba parameter. The electric field also induces frequency modulation in the associated spectrum. On the other hand, transitions that are normally allowed show, to a large extent, a parallel band effect, and accordingly they are responsible for strong optical absorption.

  19. A cylindrical furnace for absorption spectral studies

    Indian Academy of Sciences (India)

    R Venkatasubramanian

    2001-06-01

    A cylindrical furnace with three heating zones, capable of providing a temperature of 1100°C, has been fabricated to enable recording of absorption spectra of high temperature species. The temperature of the furnace can be controlled to ± 1°C of the set temperature. The salient feature of this furnace is that the material being heated can be prevented from depositing on the windows of the absorption cell by maintaining a higher temperature at both the ends of the absorption cell.

  20. Sound Absorption of Locally Resonant Sonic Materials

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-Gang; LIU Yao-Zong; WEN Ji-Hong; YU Dian-Long; WANG Gang; WEN Xi-Sen

    2006-01-01

    @@ The acoustic properties of locally resonant sonic materials with viscosity are theoretically investigated by using the multiple-scattering approach. We find that the absorption of a two-layer slab dominates the wave attenuation in the resonant frequency region under the condition of moderate or high viscous level. The fundamental mechanism operating in local resonance for absorption is investigated for the viability by the mode translation in the scattering process of a single scatterer. Finally the absorption performance in a multi-layer system is discussed.

  1. Absorption of surface acoustic waves by graphene

    Directory of Open Access Journals (Sweden)

    S. H. Zhang

    2011-06-01

    Full Text Available We present a theoretical study on interactions of electrons in graphene with surface acoustic waves (SAWs. We find that owing to momentum and energy conservation laws, the electronic transition accompanied by the SAW absorption cannot be achieved via inter-band transition channels in graphene. For graphene, strong absorption of SAWs can be observed in a wide frequency range up to terahertz at room temperature. The intensity of SAW absorption by graphene depends strongly on temperature and can be adjusted by changing the carrier density. This study is relevant to the exploration of the acoustic properties of graphene and to the application of graphene as frequency-tunable SAW devices.

  2. Gas treating absorption theory and practice

    CERN Document Server

    Eimer, Dag

    2014-01-01

    Gas Treating: Absorption Theory and Practice provides an introduction to the treatment of natural gas, synthesis gas and flue gas, addressing why it is necessary and the challenges involved.  The book concentrates in particular on the absorption-desorption process and mass transfer coupled with chemical reaction. Following a general introduction to gas treatment, the chemistry of CO2, H2S and amine systems is described, and selected topics from physical chemistry with relevance to gas treating are presented. Thereafter the absorption process is discussed in detail, column hardware is explain

  3. Coherent absorption of N00N states

    CERN Document Server

    Roger, Thomas; Lyons, Ashley; Giovannini, Daniel; Romero, Jacquiline; Jeffers, John; Padgett, Miles; Faccio, Daniele

    2016-01-01

    Recent results in deeply subwavelength thickness films demonstrated coherent control and logical gate operations with both classical and single photon light sources. However, quantum processing and devices typically involve more than one photon and non-trivial input quantum states. Here we experimentally investigate two-photon N00N state coherent absorption in a multilayer graphene film. Depending on the N00N state input phase, it is possible to selectively choose between single or two photon absorption of the input state in the graphene film. These results demonstrate that coherent absorption in the quantum regime exhibits unique features opening up applications in multiphoton spectroscopy and imaging.

  4. Theory of absorption-induced transparency

    Science.gov (United States)

    Rodrigo, Sergio G.; Martín-Moreno, L.

    2014-09-01

    Absorption induced transparency consists in a transmission peak observed in holey metal films when a molecular dye is deposited on top of it [Hutchison et al., Angew. Chem. Int. Ed. 50, 2085 (2011)]. This transmission feature appears unexpectedly close to one of the absorption energies of the molecules, hence its name. Tentative explanations pointed to strong-coupling interactions between plasmons and molecules. However, we recently demonstrated the actual mechanism behind, which takes place through a strong modification of the propagation constant of holes. We also found that absorption induced transparency occurs in single holes and it is not restricted to the optical range.

  5. Extraordinary Absorption of Decorated Undoped Graphene

    Science.gov (United States)

    Stauber, T.; Gómez-Santos, G.; de Abajo, F. Javier García

    2014-02-01

    We theoretically study absorption by an undoped graphene layer decorated with arrays of small particles. We discuss periodic and random arrays within a common formalism, which predicts a maximum absorption of 50% for suspended graphene in both cases. The limits of weak and strong scatterers are investigated, and an unusual dependence on particle-graphene separation is found and explained in terms of the effective number of contributing evanescent diffraction orders of the array. Our results can be important to boost absorption by single-layer graphene due to its simple setup with potential applications to light harvesting and photodetection based on energy (Förster) rather than charge transfer.

  6. [Dimensional fractal of post-paddy wheat root architecture].

    Science.gov (United States)

    Chen, Xin-xin; Ding, Qi-shuo; Li, Yi-nian; Xue, Jin-lin; Lu, Ming-zhou; Qiu, Wei

    2015-06-01

    To evaluate whether crop rooting system was directionally dependent, a field digitizer was used to measure post-paddy wheat root architectures. The acquired data was transferred to Pro-E, in which virtual root architecture was reconstructed and projected to a series of planes each separated in 10° apart. Fractal dimension and fractal abundance of root projections in all the 18 planes were calculated, revealing a distinctive architectural distribution of wheat root in each direction. This strongly proved that post-paddy wheat root architecture was directionally dependent. From seedling to turning green stage, fractal dimension of the 18 projections fluctuated significantly, illustrating a dynamical root developing process in the period. At the jointing stage, however, fractal indices of wheat root architecture resumed its regularity in each dimension. This wheat root architecture recovered its dimensional distinctness. The proposed method was applicable for precision modeling field state root distribution in soil.

  7. Triterpene and Flavonoid Biosynthesis and Metabolic Profiling of Hairy Roots, Adventitious Roots, and Seedling Roots of Astragalus membranaceus.

    Science.gov (United States)

    Park, Yun Ji; Thwe, Aye Aye; Li, Xiaohua; Kim, Yeon Jeong; Kim, Jae Kwang; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Park, Sang Un

    2015-10-14

    Astragalus membranaceus is an important traditional Chinese herb with various medical applications. Astragalosides (ASTs), calycosin, and calycosin-7-O-β-d-glucoside (CG) are the primary metabolic components in A. membranaceus roots. The dried roots of A. membranaceus have various medicinal properties. The present study aimed to investigate the expression levels of genes related to the biosynthetic pathways of ASTs, calycosin, and CG to investigate the differences between seedling roots (SRs), adventitious roots (ARs), and hairy roots (HRs) using quantitative real-time polymerase chain reaction (qRT-PCR). qRT-PCR study revealed that the transcription level of genes involved in the AST biosynthetic pathway was lowest in ARs and showed similar patterns in HRs and SRs. Moreover, most genes involved in the synthesis of calycosin and CG exhibited the highest expression levels in SRs. High-performance liquid chromatography (HPLC) analysis indicated that the expression level of the genes correlated with the content of ASTs, calycosin, and CG in the three different types of roots. ASTs were the most abundant in SRs. CG accumulation was greater than calycosin accumulation in ARs and HRs, whereas the opposite was true in SRs. Additionally, 40 metabolites were identified using gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS). Principal component analysis (PCA) documented the differences among SRs, ARs, and HRs. PCA comparatively differentiated among the three samples. The results of PCA showed that HRs were distinct from ARs and SRs on the basis of the dominant amounts of sugars and clusters derived from closely similar biochemical pathways. Also, ARs had a higher concentration of phenylalanine, a precursor for the phenylpropanoid biosynthetic pathway, as well as CG. TCA cycle intermediates levels including succinic acid and citric acid indicated a higher amount in SRs than in the others.

  8. Pea-root exudates and their effect upon root-nodule bacteria

    NARCIS (Netherlands)

    Egeraat, van A.W.S.M.

    1972-01-01

    The main purpose of this investigation was to study the exudation (mechanism, sites) of various compounds by roots of pea seedlings in relation to the growth of Rhizobium leguminosarum.Chapter 1 gives a survey of the literature pertaining to plant-root exudates and their influence upon soil microorg

  9. Root system markup language: toward a unified root architecture description language.

    Science.gov (United States)

    Lobet, Guillaume; Pound, Michael P; Diener, Julien; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Javaux, Mathieu; Leitner, Daniel; Meunier, Félicien; Nacry, Philippe; Pridmore, Tony P; Schnepf, Andrea

    2015-03-01

    The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow.

  10. Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields

    Science.gov (United States)

    Arai-Sanoh, Yumiko; Takai, Toshiyuki; Yoshinaga, Satoshi; Nakano, Hiroshi; Kojima, Mikiko; Sakakibara, Hitoshi; Kondo, Motohiko; Uga, Yusaku

    2014-01-01

    To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study. PMID:24988911

  11. Redirection of auxin flow in Arabidopsis thaliana roots after infection by root-knot nematodes

    NARCIS (Netherlands)

    Kyndt, Tina; Goverse, Aska; Haegeman, Annelies; Warmerdam, Sonja; Wanjau, Cecilia; Jahani, Mona; Engler, Gilbert; Almeida Engler, De Janice; Gheysen, Godelieve

    2016-01-01

    Plant-parasitic root-knot nematodes induce the formation of giant cells within the plant root, and it has been recognized that auxin accumulates in these feeding sites. Here, we studied the role of the auxin transport system governed by AUX1/LAX3 influx proteins and different PIN efflux proteins dur

  12. Etiology of phomopsis root rot in soybean

    Directory of Open Access Journals (Sweden)

    Valéria Cecília Ghissi

    2014-09-01

    Full Text Available In a survey of damages caused by soybean root rot to crops in the south of Brazil for several years, a root rot caused by Phomopsis sp has been found with increasing frequency. The primary symptoms are seen when the main root is cut longitudinally, including the death of the wood which shows white coloration and well-defined black lines that do not have a defined format. Thus, based on similarity, it has been called geographic root rot due to its aspect resembling irregular lines that separate regions on a map. In isolations, colonies and alpha spores of Phomopsis have prevailed. Pathogenicity test was done by means of inoculation in the crown of plants cultivated in a growth chamber. The geographic symptoms were reproduced in plants and the fungus Phomopsis sp. was reisolated. In soybean stems naturally infected with pod and stem blight, geographic symptoms caused by Phomopsis phaseoli are found. To the known symptoms on stems, pods and grains, that of root rot caused by P. phaseoli is now added.

  13. Chronic nerve root entrapment: compression and degeneration

    Science.gov (United States)

    Vanhoestenberghe, A.

    2013-02-01

    Electrode mounts are being developed to improve electrical stimulation and recording. Some are tight-fitting, or even re-shape the nervous structure they interact with, for a more selective, fascicular, access. If these are to be successfully used chronically with human nerve roots, we need to know more about the possible damage caused by the long-term entrapment and possible compression of the roots following electrode implantation. As there are, to date, no such data published, this paper presents a review of the relevant literature on alternative causes of nerve root compression, and a discussion of the degeneration mechanisms observed. A chronic compression below 40 mmHg would not compromise the functionality of the root as far as electrical stimulation and recording applications are concerned. Additionally, any temporary increase in pressure, due for example to post-operative swelling, should be limited to 20 mmHg below the patient’s mean arterial pressure, with a maximum of 100 mmHg. Connective tissue growth may cause a slower, but sustained, pressure increase. Therefore, mounts large enough to accommodate the root initially without compressing it, or compliant, elastic, mounts, that may stretch to free a larger cross-sectional area in the weeks after implantation, are recommended.

  14. Computing Rooted and Unrooted Maximum Consistent Supertrees

    CERN Document Server

    van Iersel, Leo

    2009-01-01

    A chief problem in phylogenetics and database theory is the computation of a maximum consistent tree from a set of rooted or unrooted trees. A standard input are triplets, rooted binary trees on three leaves, or quartets, unrooted binary trees on four leaves. We give exact algorithms constructing rooted and unrooted maximum consistent supertrees in time O(2^n n^5 m^2 log(m)) for a set of m triplets (quartets), each one distinctly leaf-labeled by some subset of n labels. The algorithms extend to weighted triplets (quartets). We further present fast exact algorithms for constructing rooted and unrooted maximum consistent trees in polynomial space. Finally, for a set T of m rooted or unrooted trees with maximum degree D and distinctly leaf-labeled by some subset of a set L of n labels, we compute, in O(2^{mD} n^m m^5 n^6 log(m)) time, a tree distinctly leaf-labeled by a maximum-size subset X of L that all trees in T, when restricted to X, are consistent with.

  15. Protein synthesis in geostimulated root caps

    Science.gov (United States)

    Feldman, L. J.

    1982-01-01

    A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

  16. 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.

  17. Root-soil air gap and resistance to water flow at the soil-root interface of Robinia pseudoacacia.

    Science.gov (United States)

    Liu, X P; Zhang, W J; Wang, X Y; Cai, Y J; Chang, J G

    2015-12-01

    During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface.

  18. Evolution of Root Characters of Soybean Varieties Developed in Different Years

    Institute of Scientific and Technical Information of China (English)

    YANG Xiu-hong; WU Zong-pu; ZHANG Guo-dong

    2002-01-01

    It was studied that the evolution of root characteristics among 42 soybean varieties developed in Heilongjiang and Jilin Province in different years. The results showed that there were differences on the root characteristics among soybean varieties. From 1950s to 1990s, root fresh weight, root volume, root surface, root dry weight, lateral root length of main root characters tendedly increased with the variable development years. The root system of the varieties in 1990s was relatively well developed compared with that in the other years. The evolutionary trend of the root system of soybean varieties was increasing in root weight, root volume, root surface and length of lateral root.

  19. A NOTE ON THE STOCHASTIC ROOTS OF STOCHASTIC MATRICES

    Institute of Scientific and Technical Information of China (English)

    Qi-Ming HE; Eldon GUNN

    2003-01-01

    In this paper, we study the stochastic root matrices of stochastic matrices. All stochastic roots of 2×2 stochastic matrices are found explicitly. A method based on characteristic polynomial of matrix is developed to find all real root matrices that are functions of the original 3×3 matrix, including all possible (function) stochastic root matrices. In addition, we comment on some numerical methods for computing stochastic root matrices of stochastic matrices.

  20. Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L. seedlings: passive or active uptake?

    Directory of Open Access Journals (Sweden)

    Jiang Ting-Hui

    2010-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment. Results The possibility that plant roots may take up phenanthrene (PHE, a representative of PAHs, via active process was investigated using intact wheat (Triticum acstivnm L. seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 μM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent Km of 23.7 μM and a Vmax of 208 nmol g-1 fresh weight h-1, suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 μM. The contribution of active uptake to total absorption was almost 40

  1. Can Crops with Greater Rooting Systems Improve Nitrogen Retention and Mitigate Emissions of Nitrous Oxide?

    Science.gov (United States)

    Decock, Charlotte; Lee, Juhwan; Barthel, Matti; Mikita, Chris; Wilde, Benjamin; Verhoeven, Elizabeth; Hund, Andreas; Abiven, Samuel; Friedli, Cordula; Conen, Franz; Mohn, Joachim; Wolf, Benjamin; Six, Johan

    2016-04-01

    It has been suggested that crops with deeper root systems could improve agricultural sustainability, because scavenging of nitrogen (N) in the subsoil would increase overall N retention and use efficiency in the system. However, the effect of plant root depth and root architecture on N-leaching and emissions of the potent greenhouse N2O remains largely unknown. We aimed to assess the effect of plant rooting depth on N-cycling and N2O production and reduction within the plant-soil system and throughout the soil profile. We hypothesized that greater root depth and root biomass will (1) increase N use efficiency and decrease N losses in the form of N leaching and N2O emissions; (2) increase N retention by shifting the fate of NH4+ from more nitrification toward more plant uptake and microbial immobilization; and (3) increase the depth of maximum N2O production and decrease the ratio of N2O:(N2O+N2) in denitrification end-products. To test these hypotheses, 4 winter wheat cultivars were grown in lysimeters (1.5 m tall, 0.5 m diameter, 3 replications per cultivar) under greenhouse conditions. Each lysimeter was equipped with an automated flux chamber for the determination of N2O surface fluxes. At 7.5, 30, 60, 90 and 120 cm depth, sampling ports were installed for the determination of soil moisture contents, as well as the collection of soil pore air and soil pore water samples. We selected two older and two newer varieties from the Swiss winter wheat breeding program, spanning a 100-year breeding history. The selection was based on previous experiments indicating that the older varieties have deeper rooting systems than the newer varieties under well watered conditions. N2O fluxes were determined twice per day on a quantum cascade laser absorption spectrometer interfaced with the automated flux chambers. Once per week, we determined concentrations of mineral N in pore water and of CO2 and N2O in the pore air. For mineral N and N2O, also natural abundance isotope deltas

  2. Effects of silicon on Oryza sativa L. seedling roots under simulated acid rain stress.

    Science.gov (United States)

    Ju, Shuming; Yin, Ningning; Wang, Liping; Zhang, Cuiying; Wang, Yukun

    2017-01-01

    Silicon (Si) has an important function in reducing the damage of environmental stress on plants. Acid rain is a serious abiotic stress factor, and Si can alleviate the stress induced by acid rain on plants. Based on these assumptions, we investigated the effects of silicon on the growth, root phenotype, mineral element contents, hydrogen peroxide (H2O2) and antioxidative enzymes of rice (Oryza sativa L.) seedling roots under simulated acid rain (SAR) stress. The results showed that the combined or single effects of Si and/or SAR on rice roots depend on the concentration of Si and the pH of the SAR. The combined or single effects of a low or moderate concentration of Si (1.0 or 2.0 mM) and light SAR (pH 4.0) enhanced the growth of rice roots, and the combined effects were stronger than those of the single treatment. A high concentration of Si (4.0 mM) or severe SAR (pH 2.0) exerted deleterious effects. The incorporation of Si (1.0, 2.0 or 4.0 mM) into SAR with pH 3.0 or 2.0 promoted the rice root growth, decreased the H2O2 content, increased the Si concentration and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities, maintained the balance of mineral element (K, Ca, Mg, Fe, Zn, and Cu) concentrations in the roots of rice seedlings compared with SAR alone. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with a low or high concentration of Si (1.0 or 4.0 mM). The observed effects were due to disruptions in the absorption and utilization of mineral nutrients and impacts on the activity of antioxidant enzymes in roots, and this conclusion suggests that the degree of rice root damage caused by acid rain might be attributed to not only acid rain but also the level of Si in the soil.

  3. Untangling the effects of root age and tissue nitrogen on root respiration in Populus tremuloides at different nitrogen supply.

    Science.gov (United States)

    Ceccon, Christian; Tagliavini, Massimo; Schmitt, Armin Otto; Eissenstat, David M

    2016-05-01

    Root respiration is a major contributor to terrestrial carbon flux. Many studies have shown root respiration to increase with an increase in root tissue nitrogen (N) concentration across species and study sites. Studies have also shown that both root respiration and root N concentration typically decrease with root age. The effects of added N may directly increase respiration of existing roots or may affect respiration by shifting the age structure of a root population by stimulating growth. To the best of our knowledge, no study has ever examined the effect of added N as a function of root age on root respiration. In this study, root respiration of 13-year-old Populus tremuloides Michx. trees grown in the field and 1-year-old P. tremuloides seedlings grown in containers was analyzed for the relative influence of root age and root N concentration independent of root age on root respiration. Field roots were first tracked using root windows and then sampled at known age. Nitrogen was either applied or not to small patches beneath the windows. In a pot experiment, each plant was grown with its root system split between two separate pots and N was applied at three different levels, either at the same or at different rates between pots. Root N concentration ranged between 1.4 and 1.7% in the field experiment and 1.8 and 2.6% in the seedling experiment. We found that addition of N increased root N concentration of only older roots in the field but of roots of all ages in the potted seedlings. In both experiments, the age-dependent decline in root respiration was largely consistent, and could be explained by a negative power function. Respiration decreased ∼50% by 3 weeks of age. Although root age was the dominant factor affecting respiration in both experiments, in the field experiment, root N also contributed to root respiration independent of root age. These results add further insight into respiratory responses of roots to N addition and mechanisms underlying the

  4. Alpha self-absorption in monazite dusts.

    Science.gov (United States)

    Terry, K W

    1995-10-01

    Measurements have been made of the self-absorption effects in monazite of alpha particles of the 232Th decay series. Samples of six size fractions of monazite were deposited on filters at different dust concentrations and then the gross alpha activity determined. Self-absorption effects were negligible in monazite particles up to 8 microns diameter provided dust concentrations were less than 1 mg cm-2. Significant self-absorption effects occurred for both larger particle sizes and higher dust loadings. As reported AMAD values in the mineral sands industry range up to 15 microns, which is equivalent to an actual mean size of 8 microns diameter monazite particle, minimal self-absorption occurs in samples collected in air monitoring programs conducted in the industry provided that dust concentrations on the filters are less than 1 mg cm-2.

  5. Performance Analysis of Solution Transportation Absorption Chiller

    Science.gov (United States)

    Kiani, Behdad; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Thermally activated advanced absorption cycles are considered promising candidates to replace CFCs, HCFCs and HFCs for residential and commercial applications. In such absorption systems, it is desirable to utilize the waste heat from industries for heating and cooling applications in commercial and residential sectors. For this purpose, it is necessary to transport energy over some distance because the waste heat source and demand are generally located apart from each other. Transportation of steam, hot water or chilled water requires high construction costs for insulation. There is an efficient method of energy transportation using absorption system called “ Solution Transportation Absorption System (STA)”. The solution is transported at an ambient temperature so that tube-insulations not required. This paper shows the simulation of the abovementioned system and the optimal result, using mathematical optimization. The optimum system with industry‧s waste heat utilization is obtained. At the end, the effect on the pollution emission and energy conservation is obtained.

  6. Absorption imaging of a single atom

    CERN Document Server

    Streed, E W; Norton, B G; Kielpinski, D

    2012-01-01

    Absorption imaging has played a key role in the advancement of science from van Leeuwenhoek's discovery of red blood cells to modern observations of dust clouds in stellar nebula. Here we show the first absorption imaging of a single atom isolated in vacuum. The simplicity of this system lets us compare our results directly to quantum theory, unlike recent work on absorption imaging of single molecules. The observed image contrast of 3.1(3)% achieved the maximum allowed by quantum theory for our setup, while the imaging resolution was on the order of the 370 nm illumination wavelength. The absorption of photons by single atoms is of immediate interest for quantum information processing (QIP). Our results also point out new opportunities in imaging of light-sensitive samples both in the optical and x-ray regimes. In particular, the dynamics of chromatin in living cells could be imaged without delivering a lethal UV dose.

  7. High performance heat pump absorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.; Longo, G.; Rossetto, L.

    1988-10-01

    Absorption heat pumps can provide high performances when operating in suitable cycles with multiple effects. This report describes some multistage cycles and evaluates the coefficient of performance realistically obtainable both in winter and summer working conditions.

  8. Absorption of light dark matter in semiconductors

    CERN Document Server

    Hochberg, Yonit; Zurek, Kathryn M

    2016-01-01

    Semiconductors are by now well-established targets for direct detection of MeV to GeV dark matter via scattering off electrons. We show that semiconductor targets can also detect significantly lighter dark matter via an absorption process. When the dark matter mass is above the band gap of the semiconductor (around an eV), absorption proceeds by excitation of an electron into the conduction band. Below the band gap, multi-phonon excitations enable absorption of dark matter in the 0.01 eV to eV mass range. Energetic dark matter particles emitted from the sun can also be probed for masses below an eV. We show that the reach for absorption of a relic kinetically mixed dark photon or pseudoscalar in semiconductors such as germanium or silicon can exceed current astrophysical and terrestrial constraints, with only a moderate exposure.

  9. Enriching Absorptive Capacity Through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper Jaap; Becker-Ritterspach, Florian; Saka-Helmhout, Ayse

    their organization’s capacity to put new knowledge to use. To address this shortcoming we conduct an in-depth comparative case study of a headquarters-initiated knowledge transfer initiative at two subsidiaries of the same MNE. The findings demonstrate that social interaction is a key requirement for subsidiary...... absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context. Second, the findings illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling or constraining local interaction patterns......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within MNEs. But how individual behaviour translates to absorptive capacity at the subsidiary level, and exactly how this is contingent on subsidiaries’ social context, remains under-addressed. This not only...

  10. Enriching Absorptive Capacity through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper J.; Saka-Helmhout, Ayse; Becker-Ritterspach, Florian

    2012-01-01

    their organization's capacity to put new knowledge to use. To address this shortcoming we conduct an in-depth comparative case study of a headquarters-initiated knowledge transfer at two subsidiaries of the same multinational enterprise. The findings demonstrate that social interaction is a prerequisite...... for subsidiary absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context and the development of local applications. The findings also illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within multinational enterprises. But how individual behaviour translates into absorptive capacity at the subsidiary level, and how this is contingent on subsidiaries' social context, remains under...

  11. Absorption mapping for characterization of glass surfaces.

    Science.gov (United States)

    Commandré, M; Roche, P; Borgogno, J P; Albrand, G

    1995-05-01

    The surface quality of bare substrates and preparation procedures take on an important role in optical coating performances. The most commonly used techniques of characterization generally give information about roughness and local defects. A photothermal deflection technique is used for mapping surface absorption of fused-silica and glass substrates. We show that absorption mapping gives specific information on surface contamination of bare substrates. We present experimental results concerning substrates prepared by different cleaning and polishing techniques. We show that highly polished surfaces lead to the lowest values of residual surface absorption. Moreover the cleaning behavior of surfaces of multicomponent glasses and their optical performance in terms of absorption are proved to be different from those of fused silica.

  12. The Driving Forces of Subsidiary Absorptive Capacity

    DEFF Research Database (Denmark)

    Schleimer, Stephanie C.; Pedersen, Torben

    2013-01-01

    The study investigates how a multinational corporation (MNC) can promote the absorptive capacity of its subsidiaries. The focus is on what drives the MNC subsidiary's ability to absorb marketing strategies that are initiated by the MNC parent, as well as how the subsidiary enacts on this absorptive...... capacity in order to compete in its focal market. The dual embeddedness of MNC subsidiaries plays a key role in this investigation, as subsidiaries belong to the MNC network and are simultaneously embedded in their host country environment. We argue that subsidiary absorptive capacity is formed...... as a purposeful response to this dual embeddedness. An analysis of marketing strategy absorptions undertaken by 213 subsidiaries reveals that MNCs can assist their subsidiaries to compete in competitive and dynamic focal markets by forming specific organizational mechanisms that are conducive to the development...

  13. Iron absorption from typical Latin American diets.

    Science.gov (United States)

    Acosta, A; Amar, M; Cornbluth-Szarfarc, S C; Dillman, E; Fosil, M; Biachi, R G; Grebe, G; Hertrampf, E; Kremenchuzky, S; Layrisse, M

    1984-06-01

    The availability and daily absorption of iron was determined by the extrinsic label method in typical lower middle to lower class diets consumed in regions of Argentina, Brazil, Chile, Mexico, Peru, and Venezuela. Differences in iron absorption from meals up to 7-fold, could be attributed to the varying contents of absorption enhancers, eg, in meat, and of inhibitors in tea, vegetables, and wheat or maize bread. The total iron available in the diets from four countries did not meet the physiological requirements for normal subjects but deficient subjects fulfilled their requirements absorbing from 1.0 to 2.1 mg/day. In five diets heme iron (6 to 24% of the total) provided 34 to 73% of the iron absorbed. These data suggest that such absorption and utilization studies may be used to correlate the prevalence of iron deficiency in a population with certain diets and to guide fortification programs.

  14. Molecular absorption in transition region spectral lines

    CERN Document Server

    Schmit, Donald; Ayres, Thomas; Peter, Hardi; Curdt, Werner; Jaeggli, Sarah

    2014-01-01

    Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not previously been detected in solar spectra. Methods: We examined spectra taken from deep exposures of plage on 12 October 2013. We observed unique absorption spectra over a magnetic element which is bright in transition region line emission and the ultraviolet continuum. We compared the absorption spectra with emission spectra that is likely related to fluorescence. Results: The absorption features require a population of sub-5000 K plasma to exist above the transition region. This peculiar stratification is an extreme deviation from the canonical structure of the chromosphere-corona boundary . The cool material is not associated with a filament or discernible coronal rain. This suggests that molecules may form in the upper solar atmosphere on small spatial scales...

  15. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a highly sensitive and compact monitor to measure light absorption from particulate matters. The fundamental of the proposed device is based on...

  16. The role of root hairs in cadmium acquisition by barley

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Ruilun; Li Huafen [Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Jiang Rongfeng, E-mail: rfjiang@cau.edu.c [Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Roemheld, Volker [Institute of Plant Nutrition, University of Hohenheim, D-70593 Stuttgart (Germany); Zhang Fusuo [Key Laboratory of Plant-Soil Interactions of the Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Zhao Fangjie [Soil Science Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2011-02-15

    The role of root hairs in Cd acquisition from soil was investigated in three pot experiments using a root hairless mutant (bald root barley, brb) and its wild-type (WT) cultivar of barley (Hordeum vulgare). brb had significantly lower concentrations and lower total amounts of Cd in shoots than WT. The Cd uptake efficiency based on total root length was 8-45% lower in brb than in WT. The difference between brb and WT increased with increasing extractable Cd in soil under the experimental conditions used. Additions of phosphate to soil decreased Cd extractability. Both soil and foliar additions of phosphate decreased root length, and root hair formation in WT. These effects resulted in decreased Cd uptake with increasing P supply. Cd uptake in WT correlated significantly with root length, root hair length and density, and soil extractable Cd. Root hairs contribute significantly to Cd uptake by barley. - Research highlights: The Cd uptake efficiency was significantly lower in brb than in WT. Additions of phosphate to soil decreased Cd extractability and Cd uptake. Both soil and foliar additions of phosphate decreased root length, and root hair formation in WT. Root hairs contribute significantly to Cd uptake by barley. - The Cd uptake efficiency based on total root length was 8-45% lower in a barley root hairless mutant than in its wild-type, indicating an important role of root hairs in Cd acquisition.

  17. [Absorption and utilization of different applied nitrogen forms by winter jujube].

    Science.gov (United States)

    Peng, Yong; Peng, Fu-tian; Zhou, Peng; Zhang, Xiao-yan

    2007-06-01

    With pot experiment, this paper studied the absorption and utilization of applied urea N, Gly N and Glu N by two years old winter jujube. The results showed that all of the three N forms could be absorbed by the winter jujube, but the absorption rate of Gly N and Glu N was less than that of urea N. Taking the absorption rate of urea N as 100%, the relative absorption rate of Gly N and Glu N by jujube leaves was 28.88% and 11.73%, respectively, and the absorbed N was mainly allocated to the leaves and neonatal branches. Jujube roots could absorb 50.48% of Gly N and 42.72% of Glu N. The transaminase activity and soluble protein content in jujube leaves were increased after the application of these three N forms, but the leaf nitrate reductase activity was enhanced significantly by urea N, decreased by Gly N, and less affected by Glu N. Compared with urea N, amino acid N could significantly increase the number of colored fruits and their colored area, as well as the content of fruit soluble solid matter.

  18. Nitrogenase Activity Associated with Halodule wrightii Roots.

    Science.gov (United States)

    Smith, G W; Hayasaka, S S

    1982-06-01

    Nitrogen fixation (acetylene reduction) associated with roots of the seagrass Halodule wrightii was measured offshore near Beaufort and Moorhead City, N.C. Rates of acetylene reduction were higher in aerobic than in anaerobic assays and were linear for up to 5 days. The temperature range for acetylene reduction was 15 to 35 degrees C with a maximum activity at 35 degrees C. Nitrogenase activity was shown to vary seasonally with highest activities occurring during warmer summer months (23 mug of N(2) fixed per m per day). At in situ temperature, nitrogenase activities associated with surface-sterilized and non-surface-sterilized roots were similar. One morphological bacterial type was isolated from surface-sterilized roots and identified as Klebsiella pneumoniae type 4B.

  19. Tree root systems and nutrient mobilization

    DEFF Research Database (Denmark)

    Boyle, Jim; Rob, Harrison; Raulund-Rasmussen, Karsten;

    Roots mobilize nutrients via deep penetration and rhizosphere processes inducing weathering of primary minerals. These contribute to C transfer to soils and to tree nutrition. Assessments of these characteristics and processes of root systems are important for understanding long-term supplies...... of nutrient elements essential for forest growth and resilience. Research and techniques have signifi cantly advanced since Olof Tamm’s 1934 base mineral index for Swedish forest soils, and basic nutrient budget estimates for whole-tree harvesting systems of the 1970s. Recent research in areas that include...... sometimes stored at depth. Other recent studies on potential release of nutrients due to chemical weathering indicate the importance of root access to deep soil layers. Release profi les clearly indicate depletion in the top layers and a much higher potential in B and C horizons. Review of evaluations...

  20. Aortic Root Enlargement or Sutureless Valve Implantation?

    Directory of Open Access Journals (Sweden)

    Nikolaos G. Baikoussis

    2016-11-01

    Full Text Available Aortic valve replacement (AVR in patients with a small aortic annulus is a challenging issue. The importance of prosthesis–patient mismatch (PPM post aortic valve replacement (AVR is controversial but has to be avoided. Many studies support the fact that PPM has a negative impact on short and long term survival. In order to avoid PPM, aortic root enlargement may be performed. Alternatively and keeping in mind that often some comorbidities are present in old patients with small aortic root, the Perceval S suturelles valve implantation could be a perfect solution. The Perceval sutureless bioprosthesis provides reasonable hemodynamic performance avoiding the PPM and providing the maximum of aortic orifice area. We would like to see in the near future the role of the aortic root enlargement techniques in the era of surgical implantation of the sutureless valve (SAVR and the transcatheter valve implantation (TAVI.

  1. Cryptographic Protocols Based on Root Extracting

    DEFF Research Database (Denmark)

    Koprowski, Maciej

    In this thesis we design new cryptographic protocols, whose security is based on the hardness of root extracting or more speci cally the RSA problem. First we study the problem of root extraction in nite Abelian groups, where the group order is unknown. This is a natural generalization of the...... construction based on root extracting. As an example of this, we modify Cramer-Shoup signature scheme such that it becomes a genericm algorithm. We discuss then implementing it in RSA groups without the original restriction that the modulus must be a product of safe primes. It can also be implemented in class......,  providing a currently acceptable level of security. This allows us to propose the rst practical blind signature scheme provably secure, without relying on heuristics called random oracle model (ROM). We obtain the protocol for issuing blind signatures by implementing our modi ed Fischlin's signing algorithm...

  2. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia-Jun; Eng, Christopher; Liu, Chang-Jun; Tappero, Ryan

    2016-06-15

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn inPhragmites australisroot system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils.Phragmites australissamples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  3. Structure of Liquid Aluminum and Hydrogen Absorption

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; DAI Yongbing; WANG Jun; SHU Da; SUN Baode

    2011-01-01

    The hydrogen content in aluminum melts at different temperature was detected. The structure in aluminum melts was investigated by molecular dynamics simulation. The first peak position of pair correlation function, atomic coordination number and viscosity of aluminum melts were calculated and they changed abnormally in the same temperature range. The mechanism of hydrogen absorption has been discussed. From molecular dynamics calculations, the interdependence between melt structural properties and hydrogen absorption were obtained.

  4. Sound absorption mapping of highway noise barrier

    OpenAIRE

    Grosso, Andrea

    2012-01-01

    International audience; Sound propagation from highway to the urban areas can be reduced using noise barriers. The general computational modeling takes typically into account sound ray lines, reflection and diffraction, although the absorption distribution over the surface in not considered. The sound absorption coefficient can be calculated using a PU probe, by the impedance measured “in situ” close by the surface. Well known methods are available on the market for estimating the sound absor...

  5. Atmospheric Absorption Parameters for Laser Propagation

    Science.gov (United States)

    2007-11-02

    high-resolution, good photometric accuracy data for numerous bands in the 3-5 Am region, using the facility at Kitt Peak National Solar Observatory. The...L49-L52 (2001). 44. A. Castrillo, G. Gagliardi, G. Casa , and L. Gianfrani, "Combined interferometric and absorption-spectroscopic technique for...from FT visible solar absorption spectra and evaluation of spectroscopic databases," JQRST 82, 133-150 (2003). 53. D. Jacquemart, R.R. Gamache, and L.S

  6. Ultrafast THz Saturable Absorption in Doped Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields.......We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields....

  7. Fluctuation sound absorption in quark matter

    CERN Document Server

    Kerbikov, B O

    2016-01-01

    We investigate the sound absorption in quark matter due to the interaction of the sound wave with the precritical fluctuations of the diquark-pair field above $T_c$. The soft collective mode of the pair field is derived using the time dependent Ginzburg-Landau functional with random Langevin forces. The strong absorption near the phase transition line may be viewed as a manifestation of the Mandelshtam-Leontovich slow relaxation time theory.

  8. Vitamin D and Intestinal Calcium Absorption

    OpenAIRE

    Christakos, Sylvia; Dhawan, Puneet; Porta, Angela; Mady, Leila J.; Seth, Tanya

    2011-01-01

    The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions. 1,25Dihydroxyvitamin D3 (1,25(OH)2D3) the hormonally active form of vitamin D, through its genomic actions, is the major stimulator of active intestinal calcium absorption which involves calcium influx, translocation of calcium throu...

  9. Water Absorption Behavior of Hemp Hurds Composites

    OpenAIRE

    Nadezda Stevulova; Julia Cigasova; Pavol Purcz; Ivana Schwarzova; Frantisek Kacik; Anton Geffert

    2015-01-01

    In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp an...

  10. The economics of solar powered absorption cooling

    Science.gov (United States)

    Bartlett, J. C.

    1978-01-01

    Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.

  11. Systemic Absorption of Nanomaterials by Oral Exposure

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Bredsdorff, Lea; Beltoft, Vibe Meister;

    This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches.......This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches....

  12. Roots Air Management System with Integrated Expander

    Energy Technology Data Exchange (ETDEWEB)

    Stretch, Dale [Eaton Corporation, Menomonee Falls, WI (United States); Wright, Brad [Eaton Corporation, Menomonee Falls, WI (United States); Fortini, Matt [Eaton Corporation, Menomonee Falls, WI (United States); Fink, Neal [Ballard Power Systems, Burnaby, BC (Canada); Ramadan, Bassem [Kettering Univ., Flint, MI (United States); Eybergen, William [Eaton Corporation, Menomonee Falls, WI (United States)

    2016-07-06

    PEM fuel cells remain an emerging technology in the vehicle market with several cost and reliability challenges that must be overcome in order to increase market penetration and acceptance. The DOE has identified the lack of a cost effective, reliable, and efficient air supply system that meets the operational requirements of a pressurized PEM 80kW fuel cell as one of the major technological barriers that must be overcome. This project leveraged Roots positive displacement development advancements and demonstrated an efficient and low cost fuel cell air management system. Eaton built upon its P-Series Roots positive displacement design and shifted the peak efficiency making it ideal for use on an 80kW PEM stack. Advantages to this solution include: • Lower speed of the Roots device eliminates complex air bearings present on other systems. • Broad efficiency map of Roots based systems provides an overall higher drive cycle fuel economy. • Core Roots technology has been developed and validated for other transportation applications. Eaton modified their novel R340 Twin Vortices Series (TVS) Roots-type supercharger for this application. The TVS delivers more power and better fuel economy in a smaller package as compared to other supercharger technologies. By properly matching the helix angle with the rotor’s physical aspect ratio, the supercharger’s peak efficiency can be moved to the operating range where it is most beneficial for the application. The compressor was designed to meet the 90 g/s flow at a pressure ratio of 2.5, similar in design to the P-Series 340. A net shape plastic expander housing with integrated motor and compressor was developed to significantly reduce the cost of the system. This integrated design reduced part count by incorporating an overhung expander and motor rotors into the design such that only four bearings and two shafts were utilized.

  13. Root resorption during orthodontic tooth movements.

    Science.gov (United States)

    Ramanathan, C; Hofman, Z

    2009-12-01

    The aim of the study was to compare the extent of maxillary incisor root resorption during different orthodontic tooth movements using three different techniques, namely the basal intrusion arch, the three component arch, and levelling of the upper dental arch with the straightwire appliance. The radiographs of 49 subjects (20 males and 29 females) with a mean age of 14.5 years were taken at two time points: in groups 1 and 2 after the levelling phase and in group 3 immediately after placement of the archwire (T1) and in all groups after a period of 6 months (T2). The amount of root resorption of the central incisors was determined at T2. The average incisor resorption was different in the three groups, with group 2 (three component arch) showing greater resorption (0.46 mm) than groups 1 (basal arch) and 3 (straightwire) of 0.26 and 0.25 mm, respectively. Analysis of variance (ANOVA) demonstrated that differences in root resorption in the three groups were not significant. Wilcoxon paired test showed that the root resorption occurring between T1 and T2 in the three groups was not significant. There was also no significant difference among the rates of resorption in the three groups. Grouping the subjects on the basis of the extent of root resorption and the biomechanics used showed differences in the percentage of subjects with the least (resorption between the three groups. This again showed that the technique of three component intrusion arch resulted in the greatest increase in root resorption.

  14. Auroral radio absorption as an indicator of magnetospheric electrons and of conditions in the disturbed auroral D-region

    Energy Technology Data Exchange (ETDEWEB)

    Collis, P.N.; Hargreaves, J.K. (Lancaster Univ. (UK)); Korth, A. (Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau (Germany, F.R.))

    1984-01-01

    In a previous paper we demonstrated a method by which the auroral radio absorption measured with a riometer can be predicted from energetic electron measurements at geosynchronous orbit. The present paper enquires to what extent the process can be inverted: what levels of magnetospheric electron flux, and of D-region production rate, electron density and incremental absorption, are predicted by a given measurement of radio absorption and what reliance can be placed on such predictions. Using data from 45 precipitation features recorded with riometers in Scandinavia and at geosynchronous orbit with GEOS-2, it is shown that electron fluxes in the ranges 20 to 40, 40 to 80 and 80 to 160 keV increase with increasing absorption and can be predicted to better than 50% for absorption events of 2 dB or greater. Electrons above 160 keV show little or no correlation with absorption. D-region production rates and electron densities can be predicted to within factors of 2 and square root of 2, respectively. It is more difficult to specify the height of the absorbing region because of uncertainty in the profile of the effective recombination coefficient. Having regard to other data, an ..cap alpha..sub(eff) profile is proposed which satisfies rocket and incoherent scatter data as well as the present calculations.

  15. Geometric absorption of electromagnetic angular momentum

    Science.gov (United States)

    Konz, C.; Benford, Gregory

    2003-10-01

    Circularly polarized electromagnetic fields carry both energy and angular momentum. We investigate the conditions under which a circularly polarized wave field transfers angular momentum to a perfectly conducting macroscopic object, using exact electromagnetic wave theory in a steady-state calculation. We find that axisymmetric perfect conductors cannot absorb or radiate angular momentum when illuminated. However, any asymmetry allows absorption. A rigorous, steady-state solution of the boundary value problem for the reflection from a perfectly conducting infinite wedge shows that waves convey angular momentum at the edges of asymmetries. Conductors can also radiate angular momentum, so their geometric absorption coefficient for angular momentum can be negative. Such absorption or radiation depends solely on the specific geometry of the conductor. The geometric absorption coefficient can be as high as 0.8, and the coefficient for radiation can be -0.4, larger than typical material absorption coefficients. We apply the results to recent experiments which spun roof-shaped aluminum sheets with polarized microwave beams. Applications of geometric, instead of material, absorption can be quite varied. Though experiments testing these ideas will be simpler at microwavelengths, the ideas work for optical ones as well.

  16. Vitamin D and intestinal calcium absorption.

    Science.gov (United States)

    Christakos, Sylvia; Dhawan, Puneet; Porta, Angela; Mady, Leila J; Seth, Tanya

    2011-12-05

    The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions. 1,25Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) the hormonally active form of vitamin D, through its genomic actions, is the major stimulator of active intestinal calcium absorption which involves calcium influx, translocation of calcium through the interior of the enterocyte and basolateral extrusion of calcium by the intestinal plasma membrane pump. This article reviews recent studies that have challenged the traditional model of vitamin D mediated transcellular calcium absorption and the crucial role of specific calcium transport proteins in intestinal calcium absorption. There is also increasing evidence that 1,25(OH)(2)D(3) can enhance paracellular calcium diffusion. The influence of estrogen, prolactin, glucocorticoids and aging on intestinal calcium absorption and the role of the distal intestine in vitamin D mediated intestinal calcium absorption are also discussed.

  17. LC/MS profiling of flavonoid glycoconjugates isolated from hairy roots, suspension root cell cultures and seedling roots of Medicago truncatula

    OpenAIRE

    Staszków, Anna; Swarcewicz, Barbara; Banasiak, Joanna; Muth, Dorota; Jasiński, Michał; Stobiecki, Maciej

    2011-01-01

    Hairy roots and suspension cell cultures are commonly used in deciphering different problems related to the biochemistry and physiology of plant secondary metabolites. Here, we address about the issue of possible differences in the profiles of flavonoid compounds and their glycoconjugates derived from various plant materials grown in a standard culture media. We compared profiles of flavonoids isolated from seedling roots, hairy roots, and suspension root cell cultures of a model legume plant...

  18. Effects of nutrition spatial heterogeneity on root traits and carbon usage by roots of Cercis chinensis seedlings in split root rooms

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length (SRL) of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nu-trition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.

  19. Root approach for estimation of statistical distributions

    Science.gov (United States)

    Bogdanov, Yu. I.; Bogdanova, N. A.

    2014-12-01

    Application of root density estimator to problems of statistical data analysis is demonstrated. Four sets of basis functions based on Chebyshev-Hermite, Laguerre, Kravchuk and Charlier polynomials are considered. The sets may be used for numerical analysis in problems of reconstructing statistical distributions by experimental data. Based on the root approach to reconstruction of statistical distributions and quantum states, we study a family of statistical distributions in which the probability density is the product of a Gaussian distribution and an even-degree polynomial. Examples of numerical modeling are given.

  20. Root approach for estimation of statistical distributions

    CERN Document Server

    Bogdanov, Yu I

    2014-01-01

    Application of root density estimator to problems of statistical data analysis is demonstrated. Four sets of basis functions based on Chebyshev-Hermite, Laguerre, Kravchuk and Charlier polynomials are considered. The sets may be used for numerical analysis in problems of reconstructing statistical distributions by experimental data. Based on the root approach to reconstruction of statistical distributions and quantum states, we study a family of statistical distributions in which the probability density is the product of a Gaussian distribution and an even-degree polynomial. Examples of numerical modeling are given. The results of present paper are of interest for the development of tomography of quantum states and processes.

  1. Tonoplast aquaporins facilitate lateral root emergence

    DEFF Research Database (Denmark)

    Reinhardt, Hagen; Hachez, Charles; Bienert, Manuela Désirée

    2016-01-01

    that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip...... could be fully rescued by expressing AtTIP2;1 under its native promoter. We conclude that TIP isoforms allow the spatial and temporal fine-tuning of cellular water transport, which is critically required during the highly regulated process of LRP morphogenesis and emergence....

  2. The Effect of Surface Heterogeneity on Cloud Absorption Estimates

    Science.gov (United States)

    Chiu, Jui-Yuan C.; Marshak, Alexander; Wiscombe, Warren J.

    2004-01-01

    This study presents a systematic and quantitative analysis of the effect of inhomogeneous surface albedo on shortwave cloud absorption estimates. We use 3D radiative transfer modeling with gradually complex clouds over a simplified surface to calculate cloud absorption. We find that averaging surface albedo always underestimates cloud absorption, and thus accounting for surface heterogeneity always enhances cloud absorption. However, the impact on cloud absorption estimates is not enough to explain the discrepancy between measured and model calculated shortwave cloud absorptions.

  3. Light absorption engineering of hydrogenated nanocrystalline silicon by femtosecond laser.

    Science.gov (United States)

    Zheng, D Q; Ma, Y J; Xu, L; Su, W A; Ye, Q H; Oh, J I; Shen, W Z

    2012-09-01

    The light absorption coefficient of hydrogenated nanocrystalline silicon has been engineered to have a Gaussian distribution by means of absorption modification using a femtosecond laser. The absorption-modified sample exhibits a significant absorption enhancement of up to ∼700%, and the strong absorption does not depend on the incident light. We propose a model responsible for this interesting behavior. In addition, we present an optical limiter constructed through this absorption engineering method.

  4. Effect of QMix, peracetic acid and ethylenediaminetetraacetic acid on calcium loss and microhardness of root dentine

    Directory of Open Access Journals (Sweden)

    Sonali Taneja

    2014-01-01

    Full Text Available Objectives: The objective of this in vitro study was to assess the effect of different chelating agents on the calcium loss and its subsequent effect on the microhardness of the root dentin. Materials and Methods: Ten single rooted lower premolars were selected. The teeth were decoronated and thick transverse sections of 2 mm were obtained from the coronal third of the root. Each section was then divided into four quarters, each part constituting a sample specimen from the same tooth for each group. The treatment groups were: Group 1 (Control: 5% Sodium hypochlorite (NaOCl for 5 min + distilled water for 5 min; Group 2: 5% NaOCl for 5 min + 17% ethylenediaminetetraacetic acid (EDTA for 5 min; Group 3: 5% NaOCl for 5 min + 2.25% Peracetic acid (PAA for 5 min and Group 4: 5% NaOCl for 5 min + QMix for 5 min respectively. The calcium loss of the samples was evaluated using the Atomic Absorption Spectrophotometer followed by determination of their microhardness using Vickers Hardness Tester. Data was analyzed using one-way ANOVA, Post hoc Tukey test and Pearson correlation. Results: The maximum calcium loss and minimum microhardness was observed in Group 3 followed by Group 2, Group 4 and Group 1. There was a statistically significant difference between all the groups except between Groups 2 and 4. Conclusions: Irrigation with NaOCl + 2.25% PAA caused the maximum calcium loss from root dentin and reduced microhardness. A negative correlation existed between the calcium loss and reduction in the microhardness of root dentin.

  5. Isolated root caps, border cells, and mucilage from host roots stimulate hyphal branching of the arbuscular mycorrhizal fungus, Gigaspora gigantea.

    Science.gov (United States)

    Nagahashi, Gerald; Douds, David D

    2004-09-01

    Unlike previous reports that have shown that water soluble and volatile compounds from roots or root exudates play an important role in precolonization events during arbuscular mycorrhizal (AM) fungus-host root interactions (Bécard & Piché 1989, Giovannetti et al. 1993), the results shown here deal with particulate and viscous fractions isolated from host roots. Root caps and a slow sedimenting particulate fraction (SSPF) were rapidly isolated and separated from Ri T-DNA transformed carrot roots (D. carota) grown in liquid culture. In addition, border cells (BC) and mucilage were isolated from aseptically grown corn seedlings (Zea mays). Root caps, SSPF (composed mainly of small root cap fragments and some BCs), BCs, and mucilage all had an associated AM fungus hyphal branching stimulator. Root caps stored for 5 d at 4 degrees C appeared to either synthesize or slowly release the branching stimulator. Also, isolated root caps from roots grown in the absence of P contained more branch stimulating activity than those isolated from roots grown in the presence of P. Although the branching stimulation activity in particulate fractions was low compared to that of the exudate, the particulate fractions can stick to the root surface at considerable distances from the root tip. This may be significant during the infection and colonization of host roots at sites far removed from the primary location of exudation.

  6. Soil Tillage Management Affects Maize Grain Yield by Regulating Spatial Distribution Coordination of Roots, Soil Moisture and Nitrogen Status.

    Science.gov (United States)

    Wang, Xinbing; Zhou, Baoyuan; Sun, Xuefang; Yue, Yang; Ma, Wei; Zhao, Ming

    2015-01-01

    The spatial distribution of the root system through the soil profile has an impact on moisture and nutrient uptake by plants, affecting growth and productivity. The spatial distribution of the roots, soil moisture, and fertility are affected by tillage practices. The combination of high soil density and the presence of a soil plow pan typically impede the growth of maize (Zea mays L.).We investigated the spatial distribution coordination of the root system, soil moisture, and N status in response to different soil tillage treatments (NT: no-tillage, RT: rotary-tillage, SS: subsoiling) and the subsequent impact on maize yield, and identify yield-increasing mechanisms and optimal soil tillage management practices. Field experiments were conducted on the Huang-Huai-Hai plain in China during 2011 and 2012. The SS and RT treatments significantly reduced soil bulk density in the top 0-20 cm layer of the soil profile, while SS significantly decreased soil bulk density in the 20-30 cm layer. Soil moisture in the 20-50 cm profile layer was significantly higher for the SS treatment compared to the RT and NT treatment. In the 0-20 cm topsoil layer, the NT treatment had higher soil moisture than the SS and RT treatments. Root length density of the SS treatment was significantly greater than density of the RT and NT treatments, as soil depth increased. Soil moisture was reduced in the soil profile where root concentration was high. SS had greater soil moisture depletion and a more concentration root system than RT and NT in deep soil. Our results suggest that the SS treatment improved the spatial distribution of root density, soil moisture and N states, thereby promoting the absorption of soil moisture and reducing N leaching via the root system in the 20-50 cm layer of the profile. Within the context of the SS treatment, a root architecture densely distributed deep into the soil profile, played a pivotal role in plants' ability to access nutrients and water. An optimal

  7. Tissue specific localization of root infection by fungal pathogens: role of root border cells.

    Science.gov (United States)

    Gunawardena, Uvini; Hawes, Martha C

    2002-11-01

    When roots of pea seedlings were inoculated uniformly with spores of Nectria haematocca or other pea pathogenic fungi, more than 90% developed lesions in the region of elongation within 3 days. More mature regions of most roots as well as the tip showed no visible signs of infection. Yet, microscopic observation revealed that 'mantles,' comprised of fungal hyphae intermeshed with populations of border cells, covered the tips of most roots. After physical detachment of the mantle, the underlying tip of most roots was found to be free of infection. Mantle-covered root tips did not respond to invasion of their border cells by activation of known defense genes unless there was invasion of the tip itself, as revealed by the presence of a lesion. Concomitant with the activation of defense genes was the induction of a cell-wall degrading enzyme whose expression is a marker for renewed production of border cells. Mantle formation did not occur in response to nonpathogens. The data are consistent with the hypothesis that border cells serve as a host-specific 'decoy' that protects root meristems by inhibiting fungal infection of the root tip.

  8. Hairy Root Induction in Helicteres isora L. and Production of Diosgenin in Hairy Roots.

    Science.gov (United States)

    Kumar, Vinay; Desai, Dnyanada; Shriram, Varsha

    2014-04-01

    Mature seeds of Helicteres isora L. were collected from seven geographical locations of Maharashtra and Goa (India) and evaluated for diosgenin (a bioactive steroidal sapogenin of prime importance) extraction and quantification. Chemotypic variations were evidenced with diosgenin quantity ranging from 33 μg g(-1) seeds (Osmanabad forests) to 138 μg g(-1) (Khopoli region). Nodal and leaf explants from in vitro-raised seedlings were used for callus and Agrobacterium-mediated transformation, respectively. Compact, hard, whitish-green callus (2.65 g explant(-1)) was obtained on MS + 13.32 μM BAP + 2.32 μM Kin after 30 days of inoculation. Various parameters including types of explant and Agrobacterium strain, culture density, duration of infection and various medium compositions were optimized for hairy root production. A. rhizogenes strain ATCC-15834 successfully induced hairy roots from leaf explants (1 cm(2)) with 42 % efficiency. Transgenic status of the roots was confirmed by PCR using rolB and VirD specific primers. Hairy roots showed an ability to synthesize diosgenin. Diosgenin yield was increased ~8 times in hairy roots and ~5 times in callus than the seeds of wild plants. Enhanced diosgenin content was associated with proline accumulation in hairy roots. This is the first report on induction of hairy roots in H. isora.

  9. [Characteristics of urea 15N absorption, allocation, and utilization by sweet-cherry (Prunus avium L.)].

    Science.gov (United States)

    Zhao, Feng-Xia; Jiang, Yuan-Mao; Peng, Fu-Tian; Gao, Xiang-Bin; Liu, Bing-Hua; Wang, Hai-Yun; Zhao, Lin

    2008-03-01

    With five-year old 'Zaodaguo' sweet-cherry (Prunus avium L.) as test material, this paper studied the characteristics of its urea 15N absorption, allocation, and utilization when applied before bud-break. The results showed that the Ndff of different organs increased gradually with time, and was higher in fine roots and storage organs at full-blooming stage. At fruit core-hardening stage, the Ndff of long shoots and leaves increased quickly, reaching to 0.72% and 0.59% , respectively. From fruit core-hardening to harvesting stage, the Ndff of fruit had a rapid increase, with the peak (1.78%) at harvesting stage. After harvest, the Ndff of neonatal organs increased slowly while that of storage organs increased quickly. At full-blooming stage, the absorbed 15N in roots was firstly allocated to storage organs, with the highest allocation rate (54.91%) in large roots. At fruit core-hardening stage, the allocation rate in fine roots and storage organs decreased from 85.43% to 55.11%, while that in neonatal branches and leaves increased to 44.89%. At harvesting stage, the allocation rate in different organs had no significant change, but after harvest, the absorbed 15N had a rapid translocation to storage organs, and the allocation rate in fine roots and storage organs reached the highest (72.26%) at flower bud differentiation stage. The 15N allocation rate in neonatal branches and leaves at flower bud differentiation stage was decreased by 19.31%, compared with that at harvesting stage. From full-blooming to flower bud differentiation stage, the utilization rate of urea 15N was increasing, and reached the peak (16.86%) at flower bud differentiation stage.

  10. Distribution, synthesis, and absorption of kynurenic acid in plants.

    Science.gov (United States)

    Turski, Michal P; Turska, Monika; Zgrajka, Wojciech; Bartnik, Magdalena; Kocki, Tomasz; Turski, Waldemar A

    2011-05-01

    Kynurenic acid (KYNA) is an endogenous antagonist of the ionotropic glutamate receptors and the α7 nicotinic acetylcholine receptor as well as an agonist of the G-protein-coupled receptor GPR35. In this study, KYNA distribution and synthesis in plants as well as its absorption was researched. KYNA level was determined by means of the high-performance liquid chromatography with fluorescence detection. KYNA was found in leaves, flowers, and roots of tested medicinal herbs: dandelion (Taraxacum officinale), common nettle (Urtica dioica), and greater celandine (Chelidoniummajus). The highest concentration of this compound was detected in leaves of dandelion--a mean value of 0.49 µg/g wet weight. It was shown that KYNA can be synthesized enzymatically in plants from its precursor, L-kynurenine, or absorbed by plants from the soil. Finally, the content of KYNA was investigated in 21 herbal tablets, herbal tea, herbs in sachets, and single herbs in bags. The highest content of KYNA in a maximum daily dose of herbal medicines appeared in St. John's wort--33.75 µg (tablets) or 32.60 µg (sachets). The pharmacological properties of KYNA and its presence in high concentrations in medicinal herbs may suggest that it possesses therapeutic potential, especially in the digestive system and should be considered a new valuable dietary supplement.

  11. [Morphology of wheat roots under low-phosphorus stress].

    Science.gov (United States)

    Sun, Haiguo; Zhang, Fusuo

    2002-03-01

    The morphology of root systems of different wheat (Triticum aestivum L.) genotypes under low-phosphorus stress were studied to determine the effects of external factors on components of root system and the early morphological indicators related to phosphorus efficiency. The number of root axes and the length of lateral root of P-deficient plant were significantly lower than those of P-sufficient plant. The length of root axis and root system, and the number of lateral roots were sharply increased under low-P stress. The number and length of root axis were significantly different under different levels of phosphorus supply and among different wheat genotypes under same phosphorus supply. This implied that the two traits (number and length of root axis) were controlled by genotype and external factors. The difference in the characteristics of lateral root of the given wheat genotypes was significant only between different levels of P supply. It showed that the traits of lateral root mainly depended on external factors. The length and number of root axis, root length, and root angle were significantly different among 6 wheat genotypes. There exited significant linear relationships between relative grain yield and the interaction of the morphological traits, and it implied that the traits could be used as early indicators of selecting high P-efficiency wheat varieties.

  12. Adjustment of Forest Ecosystem Root Respiration as Temperature Warms

    Institute of Scientific and Technical Information of China (English)

    Andrew J. Burton; Jerry M. Melillo; Serita D. Frey

    2008-01-01

    Adjustment of ecosystem root respiration to warmer climatic conditions can alter the autotrophic portion of soil respiration and influence the amount of carbon available for biomass production. We examined 44 published values of annual forest root respiration and found an increase in ecosystem root respiration with increasing mean annual temperature (MAT),but the rate of this cross-ecosystem increase (Q10 = 1.6) is less than published values for short-term responses of root respiration to temperature within ecosystems (Q10 = 2-3). When specific root respiration rates and root biomass values were examined, there was a clear trend for decreasing root metabolic capacity (respiration rate at a standard temperature) with increasing MAT. There also were tradeoffs between root metabolic capacity and root system biomass, such that there were no instances of high growing season respiration rates and high root biomass occurring together. We also examined specific root respiration rates at three soil warming experiments at Harvard Forest, USA, and found decreases in metabolic capacity for roots from the heated plots. This decline could be due to either physiological acclimation or to the effects of co-occurring drier soils on the measurement date. Regardless of the cause, these findings clearly suggest that modeling efforts that allow root respiration to increase exponentially with temperature, with Qt0 values of 2 or more, may over-predict root contributions to ecosystem CO2 efflux for future climates and underestimate the amount of C available for other uses,including net primary productivity.

  13. Anchorage of mature conifers: resistive turning moment, root-soil plate geometry and root growth orientation.

    Science.gov (United States)

    Lundström, Tor; Jonas, Tobias; Stöckli, Veronika; Ammann, Walter

    2007-09-01

    Eighty-four mature Norway spruce (Picea abies L. Karst), silver fir (Abies alba Mill) and Scots pine (Pinus sylvestris L.) trees were winched over to determine the maximum resistive turning moment (M(a)) of the root-soil system, the root-soil plate geometry, the azimuthal orientation of root growth, and the occurrence of root rot. The calculation of M(a), based on digital image tracking of stem deflection, accounted not only for the force application and its changing geometry, but also for the weight of the overhanging tree, representing up to 42% of M(a). Root rot reduced M(a) significantly and was detected in 25% of the Norway spruce and 5% of the silver fir trees. Excluding trees with root rot, differences in M(a) between species were small and insignificant. About 75% of the variance in M(a) could be explained by one of the four variables--tree mass, stem mass, stem diameter at breast height squared times tree height, and stem diameter at breast height squared. Among the seven allometric variables assessed above ground, stem diameter at breast height best described the root-soil plate dimensions, but the correlations were weak and the differences between species were insignificant. The shape of the root-soil plate was well described by a depth-dependent taper model with an elliptical cross section. Roots displayed a preferred azimuthal orientation of growth in the axis of prevailing winds, and the direction of frequent weak winds matched the orientation of growth better than that of rare strong winds. The lack of difference in anchorage parameters among species probably reflects the similar belowground growth conditions of the mature trees.

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

    NARCIS (Netherlands)

    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

  15. Rooting greenwood tip cuttings of several Populus clones hydroponically (hydroponic rooting of Populus cuttings)

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, H.M.; Hansen, E.A.; Tolsted, D.N.

    1980-01-01

    Greenwood cuttings of several Populus clones were successfully rooted with a relatively simple hydroponic method. Indolebutyric acid and naphthaleneacetic acid at concentrations of 500 to 5000 ppM applied as a quick dip to the cutting bases, a complete nutrient solution at 20 to 40% of full strength, and a solution temperature between 27 and 30/sup 0/C generally produced the best rooting performance of most clones. Cuttings propagated by the hydroponic procedure rooted faster and generally outgrew those produced by a standard method after being transplanted to pots and grown in the greenhouse.

  16. Reproducible hairy root transformation and spot-inoculation methods to study root symbioses of pea

    Directory of Open Access Journals (Sweden)

    Clemow Scott R

    2011-12-01

    Full Text Available Abstract Pea has lagged behind other model legumes in the molecular study of nodulation and mycorrhizae-formation because of the difficulty to transform its roots and its poor growth on agar plates. Here we describe for pea 1 a transformation technique which permits the complementation of two known non-nodulating pea mutants, 2 a rhizobial inoculation method which allows the study of early cellular events giving rise to nodule primordia, and 3 a targeted fungal inoculation method which allows us to study short segments of mycorrhizal roots assured to be infected. These tools are certain to advance our knowledge of pea root symbioses.

  17. Water osmotic absorption in Coleus blumei plants under salinity stress

    Directory of Open Access Journals (Sweden)

    José Ozinaldo Alves de Sena

    2006-11-01

    Full Text Available Three month old Coleus blumei plants in pots were treated with different NaCl concentrations: 0.00, 0.25, 0.50 and 1.00%. To determine the water osmotic absorption, the plants had their stems cut at 10 cm from the soil surface. The remaining stems were linked to glass tubes by flexible rubber tubes. Readings of the water column level in the glass tubes were performed at each 30 minutes, corresponding to the water osmotic absorption, with a total of eleven readings. Other Coleus blumei, with the same age, received the NaCl concentrations, and were evaluated under field conditions in terms of transpiration and stomatal resistance. A randomized complete block analysis was used with five replications. An increase of osmotic absorption was verified for all treatments up to three hours after application. Then a proportional reversion of osmotic absorption to the increases on saline concentration was observed, with a higher effect in the treatment with NaCl 1.00%, showing the increase of water loss by the roots. During this period time, the treatment showed a normal linear growth of the osmotic absorption. Transpiration was reduced proportionally to the increase of salinity concentration.Mudas envasadas de Coleus blumei, com três meses de idade, foram submetidas a diferentes concentrações de cloreto de sódio (NaCl: 0,00; 0,25; 0,50 e 1,00%. Visando determinar a absorção osmótica, as mudas tiveram seus caules cortados a 10 cm acima do solo. Os caules remanescentes foram interligados a tubos de vidro por tubos flexíveis de borracha. Foram feitas leituras (cm a cada 30 minutos dos níveis das colunas de água nos capilares, correspondentes às absorções osmóticas de água, sendo ao todo realizadas onze leituras. Em outro momento, mudas de C. blumei, com a mesma idade das anteriores, receberam as mesmas concentrações de NaCl descritas anteriormente, e, ao ar livre, foram avaliadas em termos de transpiração e resistência estomática, usando

  18. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...

  19. Aortic root replacement with a pulmonary autograft

    NARCIS (Netherlands)

    R.B. Hokken (Raymond)

    1997-01-01

    textabstractAortic valve disease in the pediatric age group is usually a consequence of congenital aortic stenosis, which may be isolated or may be a part of an anomaly of the left ventricular outflow tract or the aortic root. Management of these patients is difficult. Neonates and infants with seve

  20. The bifidogenic effect of Taraxacum officinale root.

    Science.gov (United States)

    Trojanová, I; Rada, V; Kokoska, L; Vlková, E

    2004-12-01

    The infusion of dandelion root (Taraxacum officinale) stimulated in vitro the growth of 14 strains of bifidobacteria. The utilization of oligofructans, glucose, fructose and total saccharides was determined by enzymatic and phenol-sulfuric methods. Dandelion oligofructans were important source of carbon and energy for bifidobacteria tested.

  1. Parameterizing the soil - water - plant root system

    NARCIS (Netherlands)

    Feddes, R.A.; Raats, P.A.C.

    2004-01-01

    Root water uptake is described from the local scale, to the field scale and to the regional and global scales. The local macroscopic model can be incorporated in Soil-Plant-Atmosphere Continuum (SPAC) numerical models, like the SWAP, HYSWASOR, HYDRUS, ENVIRO-GRO and FUSSIM models. These SPAC models

  2. Alkaloids from the Roots of Saccopetalum prolificum

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new alkaloid, named prolifine (1), was isolated along with four known alkaloids, liriodenine (2), 6-hydroxyonychine (3), isooncodine (4) and discretamine (5) from the roots of Saccopetalum prolificum. The structure of 1 was elucidated on the basis of spectroscopic and chemical methods.

  3. Phytochemical Investigations of Caesalpinia digyna Root

    Directory of Open Access Journals (Sweden)

    R. Srinivasan

    2011-01-01

    Full Text Available Phytochemical examination of petroleum ether extract of Caesalpinia digyna root resulted in the isolation of four compounds namely, friedelin, hexacosanoic acid, β-sitosterol and stigmasterol. These compounds have been characterized on basis of physical and spectral data. All the four compounds are being reported for the first time from this plant

  4. Hormone symphony during root growth and development.

    Science.gov (United States)

    Garay-Arroyo, Adriana; De La Paz Sánchez, María; García-Ponce, Berenice; Azpeitia, Eugenio; Alvarez-Buylla, Elena R

    2012-12-01

    Hormones regulate plant growth and development in response to external environmental stimuli via complex signal transduction pathways, which in turn form complex networks of interaction. Several classes of hormones have been reported, and their activity depends on their biosynthesis, transport, conjugation, accumulation in the vacuole, and degradation. However, the activity of a given hormone is also dependent on its interaction with other hormones. Indeed, there is a complex crosstalk between hormones that regulates their biosynthesis, transport, and/or signaling functionality, although some hormones have overlapping or opposite functions. The plant root is a particularly useful system in which to study the complex role of plant hormones in the plastic control of plant development. Physiological, cellular, and molecular genetic approaches have been used to study the role of plant hormones in root meristem homeostasis. In this review, we discuss recent findings on the synthesis, signaling, transport of hormones and role during root development and examine the role of hormone crosstalk in maintaining homeostasis in the apical root meristem.

  5. Root resorption after orthodontic intrusion and extrusion:.

    NARCIS (Netherlands)

    Han, G.; Huang, S.; Hoff, J.W. Von den; Zeng, X.; Kuijpers-Jagtman, A.M.

    2005-01-01

    The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight wee

  6. Occurrence of root parsley pathogens inhabiting seeds

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available The studies on root parsley pathogens inhabiting seeds were conducted during 1981-1988 and in 1993. Filter paper method with prefreezing and keeping under light was used. Each test sample comprised 500 seeds. Pathogenicity of collected fungal isolates was tested following two laboratory methods. 238 seed samples were studied. 18 fungal species were found but only 7 proved to be important pathogens of root parsley. The most common inhabitants of root parsley seeds were Alternaria spp. A.allernata occurred on 74,8% of seeds but only a few isolates showed to be slightly pathogenic while A.petroselini and A.radicina were higly pathogenic and inhabited 11,4 and 4,2% of seeds, respectively. The second group of important pathogens were species of Fusarium found on 3,9% of seeds. F.avenaceum dominated as it comprised 48% of Fusarium isolates, the next were as follow: F.culmorum - 20%, F.equiseti - 15%, F.solani - 8%, F.oxysporum - 7% and F.dimerum -2%. Some fungi like Botrytis cinerea, Septoria petroselini and Phoma spp. inhabited low number of seeds, respectively O,4; 0,5 and 0,8%, but they were highly pathogenic to root parsley. The fungi: Bipolaris sorokiniana, Drechslera biseptata, Stemphylium botryosum and Ulocludium consortiale showed slight pathogenicity. They were isolated from 3,8% of seeds.

  7. Pectate hydrolases of parsley (Petroselinum crispum) roots.

    Science.gov (United States)

    Flodrová, Dana; Dzúrovä, Mária; Lisková, Desana; Mohand, Fairouz Ait; Mislovicová, Danica; Malovícová, Anna; Voburka, Zdenek; Omelková, Jirina; Stratilová, Eva

    2007-01-01

    The presence of various enzyme forms with terminal action pattern on pectate was evaluated in a protein mixture obtained from parsley roots. Enzymes found in the soluble fraction of roots (juice) were purified to homogeneity according to SDS-PAGE, partially separated by preparative isoelectric focusing and characterized. Three forms with pH optima 3.6, 4.2 and 4.6 clearly preferred substrates with a lower degree of polymerization (oligogalacturonates) while the form with pH optimum 5.2 was a typical exopolygalacturonase [EC 3. 2.1.67] with relatively fast cleavage of polymeric substrate. The forms with pH optima 3.6, 4.2 and 5.2 were released from the pulp, too. The form from the pulp with pH optimum 4.6 preferred higher oligogalacturonates and was not described in plants previously. The production of individual forms in roots was compared with that produced by root cells cultivated on solid medium and in liquid one.

  8. An antileishmanial chalcone from Chinese licorice roots

    DEFF Research Database (Denmark)

    Christensen, S B; Ming, C; Andersen, L

    1994-01-01

    A bioassay guided fractionation of an extract of Chinese licorice roots led to the isolation of (E)-1-[2,4-dihydroxy-3-(3-methyl-2-butenyl)phenyl]-3-[4- hydroxy-3-(3-methyl-2-butenyl]phenyl-2-propen-1-one, which in vitro showed potent antileishmanial activity. In addition, the novel chalcone (E)-...

  9. Tapping Ancient Roots: Plaited Paper Baskets

    Science.gov (United States)

    Patrick, Jane

    2011-01-01

    With ancient roots, basket making has been practiced since the earliest civilizations, and according to textile experts, probably pre-dates pottery. This is partly conjecture since few baskets remain. It is through evidence found in clay impressions that the earliest baskets reveal themselves. Basically, basketry construction is like flat weaving.…

  10. Root canal cleaning through cavitation and microstreaming

    NARCIS (Netherlands)

    Verhaagen, B.

    2012-01-01

    We have investigated the flow from a needle using Computational Fluid Dynamics simulations and high-speed imaging experiments on sub-millimeter fluidic channels. These have shown that the flow is not effective in delivering the bleach near the bacteria, due to the complex geometry of the root canal.

  11. Quantum Dilogarithm Identities at Root of Unity

    CERN Document Server

    Ip, Ivan Chi-Ho

    2014-01-01

    We study the root of unity degeneration of cluster algebras and quantum dilogarithm identities. We prove identities for the cyclic dilogarithm associated with a mutation sequence of a quiver, and as a consequence new identities for the non-compact quantum dilogarithm at $b=1$.

  12. FiT gets CLEAN local roots

    Energy Technology Data Exchange (ETDEWEB)

    Meehan, Chris

    2012-07-01

    Feed-in tariffs are starting to take root in the US. While there is little to no hope of a national FiT policy, a growing number of cities, like Los Angeles, Gainesville, and Sacramento and states including California and Vermont are creating their own FiTs. (orig.)

  13. Boston: Community Schools from the Grass Roots

    Science.gov (United States)

    O'Neil, William F.

    1974-01-01

    In Boston, grass roots citizen pressure led to the formation of community schools to replace elementary schools. The community schools are operated by the Boston School Committee during the regular school day and by the Department of Public Facilities in the extended day and evening. (Author/DN)

  14. Dialectical roots for interest prohibition theory

    NARCIS (Netherlands)

    J.A. Bergstra

    2011-01-01

    It is argued that arguments for strict prohibition of interests must be based on the use of arguments from authority. This is carried out by first making a survey of so-called dialectical roots for interest prohibition and then demonstrating that for at least one important positive interest bearing

  15. Del Pezzo Moduli via Root Systems

    NARCIS (Netherlands)

    Colombo, E.; van Geemen, B.; Looijenga, E.J.N.

    2010-01-01

    Coble defined in his 1929 treatise invariants for cubic surfaces and quartic curves. We reinterpret these in terms of the root systems of type E6 and E7 that are naturally associated to these varieties, thereby giving some of his results a more intrinsic treatment. Our discussion is uniform for all

  16. Pharmacognostical Standardization of Tephrosia purpurea Pers Root.

    Science.gov (United States)

    Sandhya, S; Ventaka, Ramana K; Vinod, K R

    2010-07-01

    Wild Indigo or Purple Tephrosia or fish poison occurs throughout the Indian subcontinent. It is widely used in the treatment of inflammation, diabetes, rheumatism, asthma, diarrhoea and many other ailments. But so far the pharmacognostic standardization has not been reported for its proper identification. Hence the present study is a pharmacognosy work carried out for the root part. This may help in the identification of the plant species. A thin transverse section, powder microscopy, measurement of the dimensions of cell structures, fluorescence analysis and physico chemical parameters were conducted for the root. From the TS, the secondary xylem fibres and vessels were found to be the tissues of diagnostic importance. The xylem vessels were of two types: narrow and long; broad and short. The important characters in the powdered microscopy were vessel elements, fibres and xylem parenchyma cells. The different fluorescent light shades were obtained under short and long UV light for both powder as well as the extracts of the root. The proximate analysis values were also obtained in a satisfactory way. Combining all these data a suitable root profile for plant can be constructed which may help in the identification of quality of the plant part.

  17. Proofs of certain properties of irrational roots

    OpenAIRE

    Belbas, S. A.

    2009-01-01

    We give two elementary proofs, at a level understandable by students with only pre-calculus knowledge of Algebra, of the well known fact that an irreducible irrational n-th root of a positive rational number cannot be solution of a polynomial of degree less than n with rational coefficients. We also state and prove a few simple consequences.

  18. Quest for Continual Growth Takes Root

    Science.gov (United States)

    Surdey, Mary M.; Hashey, Jane M.

    2006-01-01

    In this article, the authors describe how the quest for continual growth has taken its root at Vestal Central School district. Located at the heart of upstate New York, educators at Vestal Central School district have created a spirit of "kaizen," a Japanese word meaning the relentless quest for continual improvement and higher-quality…

  19. Bacterial proteins pinpoint a single eukaryotic root.

    Science.gov (United States)

    Derelle, Romain; Torruella, Guifré; Klimeš, Vladimír; Brinkmann, Henner; Kim, Eunsoo; Vlček, Čestmír; Lang, B Franz; Eliáš, Marek

    2015-02-17

    The large phylogenetic distance separating eukaryotic genes and their archaeal orthologs has prevented identification of the position of the eukaryotic root in phylogenomic studies. Recently, an innovative approach has been proposed to circumvent this issue: the use as phylogenetic markers of proteins that have been transferred from bacterial donor sources to eukaryotes, after their emergence from Archaea. Using this approach, two recent independent studies have built phylogenomic datasets based on bacterial sequences, leading to different predictions of the eukaryotic root. Taking advantage of additional genome sequences from the jakobid Andalucia godoyi and the two known malawimonad species (Malawimonas jakobiformis and Malawimonas californiana), we reanalyzed these two phylogenomic datasets. We show that both datasets pinpoint the same phylogenetic position of the eukaryotic root that is between "Unikonta" and "Bikonta," with malawimonad and collodictyonid lineages on the Unikonta side of the root. Our results firmly indicate that (i) the supergroup Excavata is not monophyletic and (ii) the last common ancestor of eukaryotes was a biflagellate organism. Based on our results, we propose to rename the two major eukaryotic groups Unikonta and Bikonta as Opimoda and Diphoda, respectively.

  20. Bullying in nursing: roots, rationales, and remedies.

    Science.gov (United States)

    Szutenbach, Mary Pat

    2013-01-01

    Bullying and incivility are sadly, far too common in today's healthcare workplaces. This article reviews early to current literature, identifies types of bullying, offers four root causes, and suggests responses to impact these causes using Gibbs' Reflective Cycle, biblical Scripture, and an allegory "How to Swim with Sharks."

  1. 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…

  2. Nodal distances for rooted phylogenetic trees.

    Science.gov (United States)

    Cardona, Gabriel; Llabrés, Mercè; Rosselló, Francesc; Valiente, Gabriel

    2010-08-01

    Dissimilarity measures for (possibly weighted) phylogenetic trees based on the comparison of their vectors of path lengths between pairs of taxa, have been present in the systematics literature since the early seventies. For rooted phylogenetic trees, however, these vectors can only separate non-weighted binary trees, and therefore these dissimilarity measures are metrics only on this class of rooted phylogenetic trees. In this paper we overcome this problem, by splitting in a suitable way each path length between two taxa into two lengths. We prove that the resulting splitted path lengths matrices single out arbitrary rooted phylogenetic trees with nested taxa and arcs weighted in the set of positive real numbers. This allows the definition of metrics on this general class of rooted phylogenetic trees by comparing these matrices through metrics in spaces M(n)(R) of real-valued n x n matrices. We conclude this paper by establishing some basic facts about the metrics for non-weighted phylogenetic trees defined in this way using L(p) metrics on M(n)(R), with p [epsilon] R(>0).

  3. REAL ROOT ISOLATION OF SPLINE FUNCTIONS

    Institute of Scientific and Technical Information of China (English)

    Renhong Wang; Jinming Wu

    2008-01-01

    In this paper,we propose an algorithm for isolating real roots of a given univariate spline function,which is based on the use of Descartes' rule of signs and de Casteljau algorithm.Numerical examples illustrate the flexibility and effectiveness of the algorithm.

  4. Damage to root dentin during retreatment procedures

    NARCIS (Netherlands)

    Shemesh, H.; Roeleveld, A.C.; Wesselink, P.R.; Wu, M.K.

    2011-01-01

    Introduction: The aim of this study was to explore the influence of retreatment procedures on the appearance of defects on the root canal walls. Methods: Two hundred mandibular premolars were divided into 4 groups. One group was left unprepared. The rest of the teeth were prepared with ProTaper file

  5. Seasonal changes of whole root system conductance by a drought-tolerant grape root system.

    Science.gov (United States)

    Alsina, Maria Mar; Smart, David R; Bauerle, Taryn; de Herralde, Felicidad; Biel, Carme; Stockert, Christine; Negron, Claudia; Save, Robert

    2011-01-01

    The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (A(L):A(R)). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (A(R)) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (g(s)) and whole root system hydraulic conductance (k(r)) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψ(L)) for Merlot grafted onto the 1103P root system (-0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (-1.06±0.03 MPa) during spring, but dropped by approximately -0.4 MPa from spring to autumn, and were significantly lower by -0.15 MPa (-1.43±0.02 MPa) than for Merlot on 101-14Mgt (at -1.28±0.02 MPa). Surprisingly, g(s) of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35-20 mmol vine(-1) s(-1) during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (k(r)) increased from 0.004 to 0.009 kg MPa(-1) s(-1) during that same time period. The changes in k(r) could not be explained by xylem anatomy or conductivity changes of individual root

  6. Seasonal changes of whole root system conductance by a drought-tolerant grape root system

    Science.gov (United States)

    Alsina, Maria Mar; Smart, David R.; Bauerle, Taryn; de Herralde, Felicidad; Biel, Carme; Stockert, Christine; Negron, Claudia; Save, Robert

    2011-01-01

    The role of root systems in drought tolerance is a subject of very limited information compared with above-ground responses. Adjustments to the ability of roots to supply water relative to shoot transpiration demand is proposed as a major means for woody perennial plants to tolerate drought, and is often expressed as changes in the ratios of leaf to root area (AL:AR). Seasonal root proliferation in a directed manner could increase the water supply function of roots independent of total root area (AR) and represents a mechanism whereby water supply to demand could be increased. To address this issue, seasonal root proliferation, stomatal conductance (gs) and whole root system hydraulic conductance (kr) were investigated for a drought-tolerant grape root system (Vitis berlandieri×V. rupestris cv. 1103P) and a non-drought-tolerant root system (Vitis riparia×V. rupestris cv. 101-14Mgt), upon which had been grafted the same drought-sensitive clone of Vitis vinifera cv. Merlot. Leaf water potentials (ψL) for Merlot grafted onto the 1103P root system (–0.91±0.02 MPa) were +0.15 MPa higher than Merlot on 101-14Mgt (–1.06±0.03 MPa) during spring, but dropped by approximately –0.4 MPa from spring to autumn, and were significantly lower by –0.15 MPa (–1.43±0.02 MPa) than for Merlot on 101-14Mgt (at –1.28±0.02 MPa). Surprisingly, gs of Merlot on the drought-tolerant root system (1103P) was less down-regulated and canopies maintained evaporative fluxes ranging from 35–20 mmol vine−1 s−1 during the diurnal peak from spring to autumn, respectively, three times greater than those measured for Merlot on the drought-sensitive rootstock 101-14Mgt. The drought-tolerant root system grew more roots at depth during the warm summer dry period, and the whole root system conductance (kr) increased from 0.004 to 0.009 kg MPa−1 s−1 during that same time period. The changes in kr could not be explained by xylem anatomy or conductivity changes of individual root

  7. Electrical Imaging of Roots and Trunks

    Science.gov (United States)

    Al Hagrey, S.; Werban, U.; Meissner, R.; Ismaeil, A.; Rabbel, W.

    2005-05-01

    We applied geoelectric and GPR techniques to analyze problems of botanical structures and even processes, e.g., mapping root zones, internal structure of trunks, and water uptake by roots. The dielectric nature of root zones and trunks is generally a consequence of relatively high moisture content. The electric method, applied to root zones, can discriminate between old, thick, isolated roots (high resistivity) and the network of young, active, and hydraulically conductive zones (low resistivity). Both types of roots show low radar velocity and a strong attenuation caused by the dominant effect of moisture (high dielectric constant) on the electromagnetic wave propagation. Single root branches could be observed in radargrams by their reflection and diffraction parabolas. We have perfected the inversion method for perfect and imperfect cylindrical objects, such as trunks, and developed a new multielectrodes (needle or gel) ring array for fast applications on living trees and discs. Using synthetic models we tested the technique successfully and analyzed it as a function of total electrode number and configuration. Measurements at a trunk show a well established inverse relationship between the imaged resistivity and the moisture content determined from cores. The central resistivity maximum of healthy trees strongly decreases toward the rim. This agrees with the moisture decrease to the outside where active sap flow processes take place. Branching, growth anomalies (new or old shoots) and meteorological effects (sunshine and wind direction) lead to deviations of the concentric electric structure. The strongest anomalies are related to infections causing wet, rotting spots or cavities. The heartwood resistivity is highest in olive and oak trunks, intermediate in young fruit trees and lowest in cork oak trunks that are considered to be anomalously wet. Compared to acoustic tomography our electric technique shows a better resolution in imaging internal ring structures

  8. On Integrable Roots in Split Lie Triple Systems

    Institute of Scientific and Technical Information of China (English)

    A.J.CALDER(O)N MART(I)N

    2009-01-01

    We focus on the notion of an integrable root in the framework of split Lie triple systems T with a coherent 0-root space. As a main result, it is shown that if T has all its nonzero roots integrable, then its standard embedding is a split Lie algebra having all its nonzero roots integrable. As a consequence, a local finiteness theorem for split Lie triple systems, saying that whenever all nonzero roots of T are integrable then T is locally finite, is stated. Finally, a classification theorem for split simple Lie triple systems having all its nonzero roots integrable is given.

  9. External root resorption: Different etiologies explained from the composition of the human root-close periodontal membrane

    Directory of Open Access Journals (Sweden)

    Inger Kjaer

    2013-01-01

    Full Text Available Introduction: This paper summarizes different conditions, which have a well-known influence on the resorption of tooth roots. It also highlights factors important for individual susceptibility to root resorption. Furthermore, the paper focuses on idiopathic root resorption where the provoking factor is not known. The Hypothesis: The several different disturbances causing root resorption can be either orthodontically provoked or acquired by trauma, virus or congenital diseases. It is presumed that all these conditions lead to inflammatory processes in the three main tissue layers, comprising the peri-root sheet. Evaluation of the Hypothesis: This paper explains how different etiologies behind root resorption and how different phenotypic traits in root resorption can be understood from immunohistochemical studies of the human periodontal membrane close to the root and thus, gain a new understanding of the phenomenon of root resorption.

  10. Root-soil friction: quantification provides evidence for measurable benefits for manipulation of root-tip traits.

    Science.gov (United States)

    McKenzie, Blair M; Mullins, Christopher E; Tisdall, Judith M; Bengough, A Glyn

    2013-06-01

    To penetrate soil, a root requires pressure both to expand the cavity it is to occupy, σn , and to overcome root-soil friction, σf . Difficulties in estimating these two pressures independently have limited our ability to estimate the coefficient of soil-root friction, μsr . We used a rotated penetrometer probe, of similar dimensions to a root, and for the first time entering the soil at a similar rate to a root tip, to estimate σn . Separately we measured root penetration resistance (PR) Qr . Root PR was between two to four times σn . We estimated that the coefficient of root-soil friction (μsr ) was 0.21-0.26, based on the geometry of the root tip. This is slightly larger than the 0.05-0.15 characteristic of boundary lubricants. Scanning electron microscopy showed that turgid border cells lined the root channel, supporting our hypothesis that the lubricant consisted of mucilage sandwiched between border cells and the surface of the root cap and epidermis. This cell-cell lubrication greatly decreased the friction that would otherwise be experienced had the surface of the root proper slid directly past unlubricated soil particles. Because root-soil friction can be a substantial component of root PR, successful manipulation of friction represents a promising opportunity for improving plant performance.

  11. Root Induced Heterogeneity In Agricultural Soils

    Science.gov (United States)

    Gomes, C.; Gabai, R.; Weisbrod, N.; Furman, A.

    2012-12-01

    In this study we investigate the role of plant induced heterogeneity on water dynamics in agricultural soils. We conducted three experiments in two sites (one still ongoing) in which a trench was excavated in the root zone of an orchard and the subsurface, to a depth of over 1 m, was instrumented in high resolution with water content, water potential and temperature sensors. High temporal resolution monitoring of soil state was carried for over a year, period that included natural (Mediterranean) climate boundary forcing. In addition, sprinkler, flood, and spray irrigation boundary conditions were forced for short time periods to explore the infiltration process under these conditions. One site was an Avocado orchard planted in red sandy soil while the other, still on-going, is in a grape vineyards irrigated by tap and treated wastewater, planted over alluvial clayey soil. In the vineyard, we are comparing soil irrigated with fresh water to soil irrigated with treated waste water for more than 10 years. Our preliminary results indicate several interesting phenomena. First, the role of plant roots is clearly seen as the major roots act as a conduit for water (and solute), providing a fast bypass of the upper soil. Further, we identified different regions of the subsurface that apparently were of the same texture, but in practice presented very different hydraulic properties. Second, the role of these roots depends on the boundary conditions. That is, the root bypass acts differently when soil is flooded than when flow is strictly unsaturated. As expected, simulation of the experimental results show good fit only if the domain heterogeneity of soil properties was incorporated. Results for the clayey soils were not available at time of abstract submission.

  12. Root canal filling using Resilon: a review.

    LENUS (Irish Health Repository)

    Shanahan, D J

    2011-07-01

    Root canal treatment is achieved by chemo-mechanical debridement of the root canal system followed by filling. The filling material \\'entombs\\' residual bacteria and acts as a barrier which prevents the entrance of oral microorganisms and reinfection of the root canal system through microleakage. However, filling with contemporary root filling materials such as gutta-percha offers limited long-term resistance to microorganisms; as a result other materials such as Resilon have been investigated as alternatives. The aim of this review was to analyse the literature to consider whether Resilon is a suitable root canal filling material. A MEDLINE and Cochrane library search including various keyword searches identified several papers which investigated or discussed Resilon or RealSeal\\/Epiphany. Analysis of the literature demonstrated that the bulk of the literature is in vitro in nature, based largely on leakage-type studies, and demonstrates a wide variety of methodologies with conflicting findings; as a result meaningful conclusions are difficult. Within the limit of these in vitro studies Resilon appears to perform adequately in comparison to gutta-percha, however, as a result of the questionable merit of such studies, it cannot presently be considered an evidence-based alternative to the current gold standard gutta-percha. It is imperative that before Resilon is considered as a replacement material, a better understanding of the physical properties of the resin sealer and the reality of the adhesive \\'monoblock\\' are elucidated. The literature also demonstrates a paucity of quality long-term clinical outcome studies which will need to be addressed before firm conclusions can be reached.

  13. Root cap-dependent gravitropic U-turn of maize root requires light-induced auxin biosynthesis via the YUC pathway in the root apex

    Science.gov (United States)

    Suzuki, Hiromi; Yokawa, Ken; Nakano, Sayuri; Yoshida, Yuriko; Fabrissin, Isabelle; Okamoto, Takashi; Baluška, František; Koshiba, Tomokazu

    2016-01-01

    Gravitropism refers to the growth or movement of plants that is influenced by gravity. Roots exhibit positive gravitropism, and the root cap is thought to be the gravity-sensing site. In some plants, the root cap requires light irradiation for positive gravitropic responses. However, the mechanisms regulating this phenomenon are unknown. We herein report that maize roots exposed to white light continuously for ≥1–2h show increased indole-3-acetic acid (IAA) levels in the root tips, especially in the transition zone (1–3mm from the tip). Treatment with IAA biosynthesis inhibitors yucasin and l-kynurenine prevented any increases in IAA content and root curvature under light conditions. Analyses of the incorporation of a stable isotope label from tryptophan into IAA revealed that some of the IAA in roots was synthesized in the root apex. Furthermore, Zmvt2 and Zmyuc gene transcripts were detected in the root apex. One of the Zmyuc genes (ZM2G141383) was up-regulated by light irradiation in the 0–1mm tip region. Our findings suggest that IAA accumulation in the transition zone is due to light-induced activation of Zmyuc gene expression in the 0–1mm root apex region. Light-induced changes in IAA levels and distributions mediate the maize root gravitropic U-turn. PMID:27307546

  14. Molecular hydrogen absorption systems in SDSS

    CERN Document Server

    Balashev, S A; Ivanchik, A V; Varshalovich, D A; Petitjean, P; Noterdaeme, P

    2014-01-01

    We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS) II Data Release 7 and SDSS-III Data Release 9. We have selected candidates using a modified profile fitting technique taking into account that the Ly$\\alpha$ forest can effectively mimic H$_2$ absorption systems at the resolution of SDSS data. To estimate the confidence level of the detections, we use two methods: a Monte-Carlo sampling and an analysis of control samples. The analysis of control samples allows us to define regions of the spectral quality parameter space where H$_2$ absorption systems can be confidently identified. We find that H$_2$ absorption systems with column densities $\\log {\\rm N_{H_2}} > 19$ can be detected in only less than 3% of SDSS quasar spectra. We estimate the upper limit on the detection rate of saturated H$_2$ absorption systems ($\\log {\\rm N_{H_2}} > 19$) in Damped Ly-$\\alpha$ (DLA) systems to be about 7%. We provide a sample of ...

  15. Absorption mode FTICR mass spectrometry imaging.

    Science.gov (United States)

    Smith, Donald F; Kilgour, David P A; Konijnenburg, Marco; O'Connor, Peter B; Heeren, Ron M A

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here, we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image, and then, these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode "Datacubes" for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  16. Zinc absorption in inflammatory bowel disease

    Energy Technology Data Exchange (ETDEWEB)

    Valberg, L.S.; Flanagan, P.R.; Kertesz, A.; Bondy, D.C.

    1986-07-01

    Zinc absorption was measured in 29 patients with inflammatory bowel disease and a wide spectrum of disease activity to determine its relationship to disease activity, general nutritional state, and zinc status. Patients with severe disease requiring either supplementary oral or parenteral nutrition were excluded. The mean 65ZnCl2 absorption, in the patients, determined using a 65Zn and 51Cr stool-counting test, 45 +/- 17% (SD), was significantly lower than the values, 54 +/- 16%, in 30 healthy controls, P less than 0.05. Low 65ZnCl2 absorption was related to undernutrition, but not to disease activity in the absence of undernutrition or to zinc status estimated by leukocyte zinc measurements. Mean plasma zinc or leukocyte zinc concentrations in patients did not differ significantly from controls, and only two patients with moderate disease had leukocyte zinc values below the 5th percentile of normal. In another group of nine patients with inflammatory bowel disease of mild-to-moderate severity and minimal nutritional impairment, 65Zn absorption from an extrinsically labeled turkey test meal was 31 +/- 10% compared to 33 +/- 7% in 17 healthy controls, P greater than 0.1. Thus, impairment in 65ZnCl2 absorption in the patients selected for this study was only evident in undernourished persons with moderate or severe disease activity, but biochemical evidence of zinc deficiency was uncommon, and clinical features of zinc depletion were not encountered.

  17. X-ray absorption spectroscopy of metalloproteins.

    Science.gov (United States)

    Ward, Jesse; Ollmann, Emily; Maxey, Evan; Finney, Lydia A

    2014-01-01

    Metalloproteins are enormously important in biology. While a variety of techniques exist for studying metals in biology, X-ray absorption spectroscopy is particularly useful in that it can determine the local electronic and physical structure around the metal center, and is one of the few avenues for studying "spectroscopically silent" metal ions like Zn(II) and Cu(I) that have completely filled valence bands. While X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) are useful for studying metalloprotein structure, they suffer the limitation that the detected signal is an average of all the various metal centers in the sample, which limits its usefulness for studying metal centers in situ or in cell lysates. It would be desirable to be able to separate the various proteins in a mixture prior to performing X-ray absorption studies, so that the derived signal is from one species only. Here we describe a method for performing X-ray absorption spectroscopy on protein bands following electrophoretic separation and western blotting.

  18. Aerosol Absorption Measurements from LANDSAT and CIMEL

    Science.gov (United States)

    Kaufman, Y. J.; Tanre, D.; Karnieli, A.; Remer, L.; Holben, B.

    1999-01-01

    Spectral remote observations of dust properties from space and from the ground create a powerful tool for determination of dust absorption of solar radiation with an unprecedented accuracy. Absorption is a key component in understanding dust impact on climate. We use Landsat space-borne measurements at 0.47 to 2.2 micrometer over Senegal with ground-based sunphotometers to find that Saharan dust absorption of solar radiation is two to four times smaller than in models. Though dust absorbs in the blue, almost no absorption was found for wavelengths greater than 0.6 micrometer. The new finding increases by 50% recent estimated solar radiative forcing by dust and decreases the estimated dust heating of the lower troposphere. Dust transported from Asia shows slightly higher absorption probably due to the presence of black carbon from populated regions. Large-scale application of this method to satellite data from the Earth Observing System can reduce significantly the uncertainty in the dust radiative effects.

  19. The effect of root preparation technique and instrumentation length on the development of apical root cracks.

    Science.gov (United States)

    Adorno, Carlos G; Yoshioka, Takatomo; Suda, Hideaki

    2009-03-01

    The purpose of this study was to compare the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Forty extracted mandibular premolars with straight roots were randomly selected and mounted on resin blocks with simulated periodontal ligaments, and the apex was exposed. The teeth were divided into four groups of 10 teeth each for different canal preparation techniques and instrumentation lengths: group A: step-back preparation (SB) with stainless steel files (SF) using root canal length (RCL) to guide instrumentation length; group B: SB using RCL - 1 mm; group C: crown-down preparation (CD) with Profile using RCL; and group D: CD with PF using RCL - 1 mm. Digital images of the instrumentation sequence were compared for each tooth. Statistical analysis revealed a significant effect of instrumentation length (p 0.05) on the development of apical cracks.

  20. Research on the Slope Protection Mechanism of Roots

    Directory of Open Access Journals (Sweden)

    Juan Wan

    2013-08-01

    Full Text Available This study aims to investigate the slope protection mechanism of roots. In ecological slope protection, plant roots can fix soil and protect slop through biological and mechanical action. However, previous studies on the slope protection mechanism are still not deep enough and inadequate. By taking four kinds of typical plant roots along Wu-Shen Expressway as the research object, through the indoor tensile test and root morphology observation analysis, the tensile strength and ultimate tension were studied and the influence to the stability of the slope was discussed in this study. The results show that the mean ultimate tension of roots is 7.19~29.96 N. The mean tension of shrub roots is 2~4 times greater than that of herb roots. The ultimate tension of the same plant roots increases with the diameter significantly. To the range of improvement, Shrub roots exceed herb ones. It also indicates that the mean tensile strength of roots are 24.48~74.25 MPa. Compared with the steel HRB235, the tensile strength of herb roots is as great as 1/5~1/3, while Shrub roots is about 1/10~1/5. The slope stability coefficient with plant growing is a positive correlation with roots tension and root number through the sliding surface and is a negative correlation with plants weight. In addition, the slope stability coefficient is related to plant density and root morphology. The test results demonstrate that the roots tension with acute angle or right angle to the landslide surface and the roots shear stiffness with obtuse angle can improve the performance of slope’s anti-slide. Four kinds of plants can improve the stability coefficient of shallow soil. As for the slope protection effect, herbage is superior to shrub. In general, grass-shrub mixed community is the ideal system for slope protection.