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1

Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera Stokes).  

PubMed

Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells. PMID:10615873

Hong, D H; Han, S B; Lee, C W; Park, S H; Jeon, Y J; Kim, M J; Kwak, S S; Kim, H M

1999-12-01

2

Cytotoxicity of urushiols isolated from sap of Korean lacquer tree ( Rhus vernicifera stokes)  

Microsoft Academic Search

Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were\\u000a below 4 ?g\\/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols\\u000a suggesting that they would

Dong Ho Hong; Sang Bae Han; Chang Woo Lee; Se Hyung Park; Young Jin Jeon; Myong-Jo Kim; Sang-Soo Kwak; Hwan Mook Kim

1999-01-01

3

Enzymatic dehydrogenative polymerization of urushiols in fresh exudates from the lacquer tree, Rhus vernicifera DC.  

PubMed

Fresh exudates from the lacquer tree, Rhus vernicifera DC, were extracted with acetone and the solution was chromatographed to isolate monomer, dimer, trimer, and oligomer fractions of urushiols. Constituents of the monomeric and dimeric fractions were then identified by two-dimensional (2D) 1H-13C heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond coherence (HMBC) NMR spectroscopic techniques. The results showed that the monomeric fraction contained 3-[8'Z,11'E,13'Z-pentadecatrienyl]catechol (1), 3-[8'Z,11'Z,14'-pentadecatrienyl]catechol (2), and 3-pentadecanyl]catechol (3), which was verified by HPLC analysis. The dimeric fraction contained 8'-(3' ',4' '-dihydroxy-5' '-alkenyl)phenyl-3-[9'E,11'E,13'Z-pentadecatrienyl]catechol (4), 14'-(3' ',4' '-dihydroxy-5' '-alkenyl)phenyl-3-[8'Z,10'E,12'E-pentadecatrienyl]catechol (5), 2-hydroxyl-3- or -6-alkenylphenyl ethyl ether (6), 14'-(3' ',4' '-dihydroxy-2' '-alkenyl)phenyl-3-[8'Z,10'E,12'E-pentadeca-trienyl]catechol (7), 15'-(2' '-hydroxy-3' '- or -6' '-alkenyl)phenyloxy-3-[8'Z,11'Z,13'E)-pentadecatrienyl]catechol (8), 14'-(2' ',3' '-dihydroxy-4' '-alkenyl)phenyl-3-[8'Z,10'E,12'E-pentadecantrienyl]catechol (9), 1,1',2,2'-tetrahydroxy-6,6'-dialkenyl-4,3'-biphenyl (10), 1,1',2,2'-tetrahydroxy-6,6'-dialkenyl-4,4'-biphenyl (11), 1,1',2,2'-tetrahydroxy-6,6'-dialkenyl-5,4'-biphenyl (12), and 1,2,1'-trihydroxy-6,6'-dialkenyldibenzofuran (13) as constituents. In addition, dimeric ethers and peroxides, such as compounds 14 and 15, were produced by autoxidation of monomeric urushiols in atmospheric air. The possible reaction mechanisms for the dehydrogenative polymerization of urushiols by Rhus laccase present in the fresh raw exudates under the atmospheric oxygen are discussed on the basis of structures identified. This is of primary importance because the use of the urushi exudates as coating materials does not involve organic solvents and is an environmentally friendly process. PMID:17319686

Harigaya, Sayoko; Honda, Takayuki; Rong, Lu; Miyakoshi, Tetsuo; Chen, Chen-Loung

2007-03-21

4

In vitro antibacterial and morphological effects of the urushiol component of the sap of the Korean lacquer tree (Rhus vernicifera Stokes) on Helicobacter pylori.  

PubMed

Eradication regimens for Helicobacter pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, alternative anti-H. pylori or supportive antimicrobial agents with fewer disadvantages are necessary for the treatment of H. pylori. We investigated the pH-(5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) and concentration (0.032, 0.064, 0.128, 0.256, 0.514, and 1.024 mg/mL)-dependent antibacterial activity of crude urushiol extract from the sap of the Korean lacquer tree (Rhus vernicifera Stokes) against 3 strains (NCTC11637, 69, and 219) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 min after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. All strains survived only within pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 mg/mL to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 min following incubation with the 1xminimal inhibitory concentrations of urushiol. The results of this work suggest that urushiol has potential as a rapid therapeutic against H. pylori infection by disrupting the bacterial cell membrane. PMID:20191039

Suk, Ki Tae; Kim, Hyun Soo; Kim, Moon Young; Kim, Jae Woo; Uh, Young; Jang, In Ho; Kim, Soo Ki; Choi, Eung Ho; Kim, Myong Jo; Joo, Jung Soo; Baik, Soon Koo

2010-03-01

5

In vitro Antibacterial and Morphological Effects of the Urushiol Component of the Sap of the Korean lacquer tree (Rhus vernicifera Stokes) on Helicobacter pylori  

PubMed Central

Eradication regimens for Helicobacter pylori infection have some side effects, compliance problems, relapses, and antibiotic resistance. Therefore, alternative anti-H. pylori or supportive antimicrobial agents with fewer disadvantages are necessary for the treatment of H. pylori. We investigated the pH-(5.0, 6.0, 7.0, 8.0, 9.0, and 10.0) and concentration (0.032, 0.064, 0.128, 0.256, 0.514, and 1.024 mg/mL)-dependent antibacterial activity of crude urushiol extract from the sap of the Korean lacquer tree (Rhus vernicifera Stokes) against 3 strains (NCTC11637, 69, and 219) of H. pylori by the agar dilution method. In addition, the serial (before incubation, 3, 6, and 10 min after incubation) morphological effects of urushiol on H. pylori were examined by electron microscopy. All strains survived only within pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged from 0.064 mg/mL to 0.256 mg/mL. Urushiol caused mainly separation of the membrane, vacuolization, and lysis of H. pylori. Interestingly, these changes were observed within 10 min following incubation with the 1×minimal inhibitory concentrations of urushiol. The results of this work suggest that urushiol has potential as a rapid therapeutic against H. pylori infection by disrupting the bacterial cell membrane.

Suk, Ki Tae; Kim, Hyun Soo; Kim, Moon Young; Kim, Jae Woo; Uh, Young; Jang, In Ho; Kim, Soo Ki; Choi, Eung Ho; Kim, Myong Jo; Joo, Jung Soo

2010-01-01

6

Gene expression profiling in the human keratinocyte cell line, hacat exposed to urushiol isolated from sap of korean lacquer tree ( Rhus verniciflua Stokes)  

Microsoft Academic Search

Rhus verniciflua Stokes (RVS) is a common poison ivy that causes allergy dermatitis. However, RVS has been widely used in Korea as a traditional\\u000a food preservative and herb. RVS sensitization on skin involves the activation of Langerhans cells and keratinocytes, as well\\u000a as T cell-mediated reaction. While keratinocytes are the first line of immune defense against injury and infection on

Ju Youn Park; Jae Ho Chang; Myong Jo Kim; Ju Sung Kim; Soo-Ki Kim

2010-01-01

7

Studies on Acetone Powder and Purified Rhus Laccase Immobilized on Zirconium Chloride for Oxidation of Phenols  

PubMed Central

Rhus laccase was isolated and purified from acetone powder obtained from the exudates of Chinese lacquer trees (Rhus vernicifera) from the Jianshi region, Hubei province of China. There are two blue bands appearing on CM-sephadex C-50 chromatography column, and each band corresponding to Rhus laccase 1 and 2, the former being the major constituent, and each had an average molecular weight of approximately 110?kDa. The purified and crude Rhus laccases were immobilized on zirconium chloride in ammonium chloride solution, and the kinetic properties of free and immobilized Rhus laccase, such as activity, molecular weight, optimum pH, and thermostability, were examined. In addition, the behaviors on catalytic oxidation of phenols also were conducted.

Lu, Rong; Miyakoshi, Tetsuo

2012-01-01

8

Pulse-radiolysis studies on the interaction of one-electron reduced species with blue oxidases. Reduction of native and type-2-copper-depleted Vietnamese-lacquer-tree and Japanese-lacquer-tree laccases.  

PubMed Central

The interactions of one-electron reduced metronidazole (ArNO2.-) and O2.- with native and Type-2-copper-depleted Vietnamese- and Japanese-lacquer-tree laccases were studied in aqueous solution at pH 6.0 and 7.4 by using the technique of pulse radiolysis. On reaction with ArNO2.-, in the absence of O2, the holo- and the Type-2-copper-depleted proteins accept, with reduction of Type 1 copper, 2 and 1 reducing equivalents respectively. On reaction with O2.- of both holo- and Type-2-copper-depleted Vietnamese-lacquer-tree laccase, almost complete reduction of Type 1 copper was observed and, after completion of the reaction, some (less than 20%) reoxidation of Type 1 copper occurs. Reduction of Type 1 copper of the laccases by these one-electron donors occurs via a bimolecular step; however, the rate of reduction of Vietnamese-lacquer-tree laccase is over 10 times that of Japanese-lacquer-tree laccase. It is inferred that electrons enter the protein via Type 1 copper with, in the case of the holoprotein, subsequent rapid intramolecular transfer of 1 reducing equivalent within the protein. Furthermore it is suggested that intra-molecular electron transfer to Type 3 copper atoms is slow and, in the case of Type-2-copper-depleted protein, may not occur. This slow process may partially account for the variation of the catalytic activities of 'blue' oxidases.

O'Neill, P; Fielden, E M; Morpurgo, L; Agostinelli, E

1984-01-01

9

Applied analysis of lacquer films based on pyrolysis-gas chromatography/mass spectrometry.  

PubMed

Ancient lacquer film, a Nanban lacquer film, an old lacquer-ware object imported from an Asian country, and the Baroque and Rococo lacquer films were analyzed by pyrolysis-gas chromatography/mass spectrometry. Compared with the results of the natural lacquer film, it was revealed that the ancient lacquer film and Nanban lacquer film were made from Rhus vernicifera, and the old lacquer-ware imported from an Asian country was made from Melanorrhoea usitata. However, the Baroque and Rococo lacquer films obtained from the Doerner Institute in Munich, Germany were made from natural resins. 3-Pentadecylcatechol (MW=320) (urushiol), 3-heptadecylcatechol (MW=348) (laccol), and 4-heptadecylcatechol (MW=348) (thitsiol) were the main products of the pyrolysis of R. vernicifera, Rhus succedanea, and M. usitata. PMID:18970777

Lu, Rong; Kamiya, Yukio; Miyakoshi, Tetsuo

2006-09-15

10

Lacquer poisoning  

MedlinePLUS

Poisoning from lacquers is due to hydrocarbons, which are substances that contain only hydrogen and carbon. ... Mirkin DB. Benzene and related aromatic hydrocarbons. In: Shannon MW, ... of Poisoning and Drug Overdose . 4th ed. Philadelphia, Pa: ...

11

Characterization of lipid components of Melanorrhoea usitata lacquer sap.  

PubMed

The lipid component of Melanorrhoea usitata lacquer sap isolated by acetone was analyzed and compared to synthesized omega-phenylalkylcatechols and omega-phenylalkylphenols. In addition, laccol and urushiol analogues synthesized in our laboratory were used as standard materials to analyze the lipid component of the Myanmar lacquer sap. The GC and GC/MS measurements confirmed the results of Kumanotani and Du that neither omega-phenylalkylcatechol nor omega-phenylalkylphenol exist in the lacquer saps from Rhus vernicifera and R. succedanea. PMID:19071488

Rong, Lu; Yukio, Kamiya; Tetsuo, Miyakoshi

2007-03-15

12

Structural study of oriental lacquer films during the hardening process.  

PubMed

Oriental lacquer is the natural resin obtained by tapping lac trees. It hardens into a tough and insoluble film. The extreme hardness and insolubility are some of the most important functions, which are required for industrial coating materials. In this study, two kinds of oriental lacquer films, traditionally named Kiurushi (raw urushi) and Kuromeurushi produced by two different pretreatments, were analyzed during hardening with Fourier transform infrared spectroscopy (FT-IR), thermogravimetry/differential thermal analysis-mass spectrometry (TG/DTA-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to investigate their functional expression process. Typical functional groups of the lacquer films were detected by FT-IR. The TG/DTA-MS curves clarified that the thermal degradation of the lacquer films gradually began at around 200 degrees C, and reached the fastest rate at 400-500 degrees C. Apparently, FT-IR and TG/DTA-MS could not reveal any difference between the films. On the other hand, Py-GC/MS revealed differences between the films in the peak area ratios of 3-pentadecenylcatechol to 3-pentadecylcatechol and 3-pentadecadienylcatechol to 3-pentadecylcatechol. The ratios of Kiurushi lacquer film were higher than those of Kuromeurushi lacquer film. Both ratios, furthermore, decreased during hardening due to polymerization of the alkenylcatechols into an urushiol polymer skeleton comprising nucleus-side chain and side chain-side chain cross-linkages with 3-pentadecylcatechol at the terminal. The present results suggest that the reaction rate of these cross-linkages in Kuromeurushi lacquer film is faster than that in Kiurushi lacquer film. A good correlation was found between the peak area ratios obtained by Py-GC/MS and hardness obtained by pencil hardening testing. Oriental lacquer expresses the functions - an extreme hardness and insolubility - accelerating the nucleus-side chain and side chain-side chain cross-linkages. Furthermore, it has become clear that the traditional treatments called Nayashi and Kurome effectively accelerate the hardening rate by activating the cross-linkages. PMID:18970743

Niimura, Noriyasu; Miyakoshi, Tetsuo

2006-08-15

13

Hyposensitization to urushiol among Japanese lacquer craftsmen: results of patch tests on students learning the art of lacquerware.  

PubMed

8 subjects learning the art of lacquerware were patch tested to urushiol before and after contact with lacquer, in order to document whether hyposensitization to urushiol occurred among Japanese lacquer craftsmen. Simultaneously, we performed patch tests on 2 urushiol-sensitized controls who had no contact with lacquer during the investigation. Lacquer is made from the sap of the Japanese lacquer tree and raw lacquer is composed of 60-65% urushiol and its oligomer. 5 of the 8 subjects showed positive reactions to urushiol 1 month after their first contact. They became negative or less positive after prolonged (9 or 10 months) exposure to lacquer. As reactions to urushiol decreased, dermatitis became less severe. Controls showed consistently high reactions. However, 1 subject showed persistently strong reactions to urushiol. Unlike the other 7 subjects, he was previously sensitized to urushiol before the first contact with lacquer. The remaining 2 subjects showed no reaction throughout our investigation. These results strongly suggest that hyposensitization to urushiol does occur among Japanese lacquer craftsmen. PMID:1839723

Kawai, K; Nakagawa, M; Kawai, K; Liew, F M; Yasuno, H

1991-11-01

14

Recent advances in research on lacquer allergy.  

PubMed

Allergic contact dermatitis caused by contact with lacquer sap and lacquerware affects the welfare of lacquer workers and the lacquerware industry. Many studies of the mechanism of urushiol allergy, including animal models, have been carried out and have established several hypotheses. In order to provide a comprehensive understanding of lacquer allergy, we review recent advances in the research on lacquer allergy including the chemical properties of lacquer lipid components, allergic mechanism analyses, immunological explanations, allergy medications, and the prevention combined with the research results from our laboratory. PMID:22015566

Ma, Xiao-ming; Lu, Rong; Miyakoshi, Tetsuo

2012-03-01

15

Ciclopirox nail lacquer: a brush with onychomycosis.  

PubMed

Ciclopirox nail lacquer solution 8%, effective and safe for the treatment of dermatophyte onychomycosis of mild-to-moderate severity, covers a broad-spectrum of organisms and also may be effective in onychomycosis caused by Candida species and nondermatophyte molds. In addition, ciclopirox nail lacquer may be an important adjunct to oral antifungal therapy in certain presentations (eg, lateral onychomycosis, longitudinal spike, dermatophytoma, extensive onycholysis) that might respond poorly to oral antifungal therapy alone. Combination therapy with an oral antifungal agent may reduce the duration and cumulative dosage of oral therapy. In some cases, however, surgical therapies may be preferred or needed in addition to topical nail lacquer treatment. Ciclopirox nail lacquer also may be valuable in the treatment of early cases of reinfection and relapse. Treatment with ciclopirox nail lacquer for onychomycosis has a favorable risk-benefit ratio. Studies to determine the role of combination oral and topical nail lacquer therapy for the management of onychomycosis are needed. PMID:11665723

Gupta, A K

2001-08-01

16

Lacquer polishing of X-ray optics  

NASA Technical Reports Server (NTRS)

Techniques for polishing figured X-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth-wave in red light and very effectively covers surface roughness with spatial wavelengths less than about 0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient X-ray reflectivity.

Catura, R. C.; Joki, E. G.; Roethig, D. T.; Brookover, W. J.

1987-01-01

17

Polymerized Urushiol of the Commercially Available Rhus Product in Korea  

PubMed Central

Background Systemic contact dermatitis commonly occurs with the intake of rhus (boiled chicken with rhus) as a health food and a folk medicine to cure gastrointestinal diseases in Korea. Rhus companies insist they have the technology for rhus detoxification. However, the numbers of systemic allergic contact dermatitis patients, caused by rhus, have not decreased. The principle of present techniques for rhus detoxification is the induction of the polymerization of urushiol, but polymerized urushiol may still have antigenicity, although to a diminished degree. The Korean Food and Drug Administration (KFDA) has a regulation to control urushiol use as a food. However, the laboratory method that KFDA uses for detection of rhus can only detect the urushiol monomer. Objective We conducted experiments to detect polymerized urushiol in rhus products, which were considered not to include urushiol by the KFDA. Methods Rhus product approved by the KFDA was separated with chloroform. The chloroform fractionation was accomplished on a recycle HPLC system. Four peaks were achieved and evaporated to give an amorphous powder. Each powder was analyzed on a NMR system and mass spectrometer. Results The material considered to be urushiol dimer, with a 638 molecular weight (MW), was detected in one of the four powders as per the HPLC peaks. Conclusion We concluded that commercially available rhus product is comprised of material considered to be urushiol dimer. Therefore, even if the antigenicity of the rhus products is low, this product may cause adverse effects and is not completely detoxified.

Cheong, Seung Hyun; Choi, You Won; Min, Byung Sun

2010-01-01

18

Ciclopirox nail lacquer topical solution 8%.  

PubMed

Ciclopirox nail lacquer 8% (Penlac, Aventis Pharma) was approved by the US FDA in December 1999, as a component of a comprehensive management program, for use in immunocompetent patients who have mild to moderate onychomycosis of the fingers and toes without lunula involvement due to Trichophyton rubrum. The comprehensive management program includes removal of the unattached, infected nails as frequently as once per month, by a health care professional who has special competence in the diagnosis and treatment of nail disorders, including minor nail procedures. The nail lacquer is not approved in Canada. PMID:11027420

Gupta, A K

2000-01-01

19

Ciclopirox nail lacquer and podiatric practice.  

PubMed

Ciclopirox 8% nail lacquer has recently been approved by the US Food and Drug Administration (FDA) for the management of mild-to-moderate dermatophytic onychomycosis not involving the lunula. Previously, the agents that were approved for the treatment of dermatophytic pedal onychomycosis--griseofulvin, itraconazole, and terbinafine--were administered orally. When ciclopirox nail lacquer is used, it is recommended that the infected nail undergo debridement by a health-care professional as frequently as monthly. It is important to be aware of the circumstances under which debridement of the mycotic nail may be considered medically necessary and therefore potentially eligible for reimbursement by third-party payers. For many nail presentations, nail debridement is an important component of a treatment protocol involving either the oral medications or the topical lacquer, as it serves to reduce the fungal load and ameliorate symptoms. With the availability of a new FDA-approved topical treatment alternative, it remains to be seen if podiatrists will embrace the definitive treatment of onychomycosis using the newer oral agents, the new nail lacquer, or both in combination with nail debridement to treat the disease. PMID:11107711

Gupta, A K; Malkin, K F

2000-01-01

20

On the UV-induced polymeric behavior of Chinese lacquer.  

PubMed

To dry Chinese lacquer rapidly for the protection and restoration of archeological findings coated by lacquer or excavated lacquer wares and the development of new application of this lacquer, we carried out UV curing technology to improve its curing rate using a high-pressure mercury lamp as a UV source in the absence of any additional photoinitiator. The effects of mainly specific components in Chinese lacquer sap and the role of each reactive group of urushiol, namely hydroxyl groups, hydrogen on the phenyl ring, and olefins in the side chain, in the course of UV exposure were well-investigated. The UV-cured Chinese lacquer films were also characterized by FT-IR, (1)H NMR, SEM, TGA, and Py-GC/MS. The results showed that urushiol was the main component to form Chinese lacquer films, and decomposed to generate the urushiol semiquinone radicals, which sequentially induced the polymerization of Chinese lacquer by radical polymerization, as well as radical substitution under UV irradiation. In addition, the TG analysis suggested that polysaccharide and glycoproteins were integrated with the UV-cured films by covalent bonding. Furthermore, this method could be suitable to fast cure other phenol bearing long aliphatic unsaturated chain, such as CNSL. PMID:21190328

Xia, Jianrong; Lin, Jinhuo; Xu, Yanlian; Chen, Qinhui

2011-02-01

21

Ciclopirox nail lacquer solution 8% in the 21st century.  

PubMed

Ciclopirox nail lacquer solution 8% has been shown to be effective in the treatment of dermatophyte onychomycosis of mild to moderate severity Other studies report the effectiveness of ciclopirox nail lacquer in onychomycosis caused by Candida sp and nondermatophyte molds. Ciclopirox nail lacquer may also be valuable in the treatment of early cases of reinfection/relapse. Ciclopirox nail lacquer solution 8% may be an important adjunct to oral antifungal therapy in certain presentations that might be poorly responsive to oral antifungal therapy alone (eg, lateral onychomycosis, longitudinal spike, dermatophytoma, and extensive onycholysis). In some cases, surgical therapies may need to be considered in addition to, or in preference to, topical nail lacquer treatment. The use of ciclopirox nail lacquer solution 8% as an adjunct to oral antifungal therapy may widen the spectrum of activity of the combination because of the broad spectrum of coverage provided by the lacquer. The use of combination therapy may be synergistic in terms of efficacy, enabling a reduction in the duration and cumulative dosage of oral therapy. This could result in a decrease in the frequency and severity of systemic adverse effects associated with the oral antimycotics and the need to be vigilant about drug interactions. Studies need to be conducted to determine the place of combination oral and topical lacquer therapy in the management of onychomycosis. PMID:11051138

Gupta, A K; Baran, R

2000-10-01

22

Antioxidant activity of extract of Rhus oxyacantha root cortex.  

PubMed

In the present study, the root extract of Rhus oxyacantha contained 25.33 mg of catechin equivalent per mg of fresh wt and was found rich in proanthocyanidins compared to vine shoot, grape pips and leaves. The chromatographic analysis of the extract suggested the presence of (+) catechin, (-) epicatechin -3-O-gallate as well as proanthocyanidinic oligomers and polymers. Root cortex inhibited the ascorbic acid oxidation by dioxygen. It also prevented DDT-induced thymocytes death in a dose-dependent manner. The results suggested antioxidant property of root extract of Rhus oxyacantha which could be ascribed to its free radical scavenging nature. PMID:16538865

Tebourbi, Olfa; Trabelsi, Chiraz; Ben Nasr, Cherif; Sakly, Mohsen

2006-03-01

23

[Therapy with ciclopirox lacquer of onychomycoses caused by molds].  

PubMed

60 patients, suffering from an onychomycosis produced by molds were treated for a maximum of 6 months with ciclopirox nail lacquer (8%). These molds determined by culture were Scopulariopsis brevicaulis (51 x), Aspergillus niger (6 x), Aspergillus fumigatus (2 x) and Hendersonula toruloidea. Anamnesis gave no hints, why molds were the causing fungi of onychomycosis. The achieved mycological cure rate was determined with 90% (culture) respectively 85% (KOH preparation). The local treatment with ciclopirox nail lacquer was well tolerated by all patients during the entire treatment period of max. 6 months. No side effects occurred. The local therapy with ciclopirox nail lacquer proved to be as effective in the treatment of onychomycosis caused by molds as in the treatment of onychomycosis due to dermatophytes and yeasts. PMID:7854374

Ulbricht, H; Wörz, K

1994-01-01

24

Homoeopathic Arnica and Rhus toxicodendron for delayed onset muscle soreness  

Microsoft Academic Search

We intend to develop a simple, reproducible, clinical model to test the null hypothesis thatthe effects of ultramolecular homoeopathic preparations are always equivalent to placebo. A pilot of a randomized, double-blind, placebo-controlled study was conducted to assess the effects of Arnica and Rhus tox 30c on delayed onset muscle soreness. 50 healthy volunteers undertook a standard bench-stepping exercise, with outcome

N. Jawara; G. T. Lewith; A. J. Vickers; M. A. Mullee; C. Smith

1997-01-01

25

Transungual delivery of ketoconazole using novel lacquer formulation.  

PubMed

Onychomycosis, a common fungal infection of the nail, can have a substantial impact on quality of life. The success of topical therapy for onychomycosis depends on effective penetration, which can be enhanced using an appropriate delivery method. This study evaluated the effectiveness of a novel topical lacquer on enhancing [(14)C]-ketoconazole penetration by comparing nail absorption, nail distribution, and nail penetration of [(14)C]-ketoconazole dissolved in the novel lacquer versus a commercial ketoconazole cream. Using the in vitro finite dose model, the formulations were applied daily to human nail plates for 7 days. Drug absorption was measured by monitoring rate of appearance in each nail layer and the supporting bed. After the multiple day treatment, cumulative concentrations of ketoconazole formulated in novel lacquer in the deep nail layer and the nail bed were significantly greater than cumulative concentrations of commercial ketoconazole (p<0.05), as well as several orders of magnitude greater than the minimal inhibitory concentration (MIC) deemed necessary to inhibit the growth of causative dermatophytic and yeast species. These results suggest that this novel ketoconazole lacquer has the potential to be an effective topical treatment for onychomycosis. PMID:24029171

Hafeez, Farhaan; Hui, Xiaoying; Chiang, Audris; Hornby, Sidney; Maibach, Howard

2013-11-18

26

Tales in Sprinkled Gold: Japanese Lacquer for European Collectors  

NSDL National Science Digital Library

One of the John Paul Getty Museum's online exhibits features Japanese lacquered objects from the Victoria and Albert Museum that were popular among European collectors in the 17th-19th centuries. The highlight of the exhibit is the Mazarin chest, which can be viewed as a slideshow by clicking on "Launch Slideshow", near the top far right hand side of the homepage. Visitors can view the chest from several different angles, use a zoom feature, and pan the images using the arrows below the slideshow images. However, dragging the cursor on the image, instead of using the arrows, allows for more control. Visitors can watch a video entitled "The Making of Japanese Lacquer", by clicking on the link on the far right hand side of the homepage, underneath "Launch Slideshow". For visitors lucky enough to visit the Getty Museum, a multitude of related events can be found under the "Events" tab near the top of the page. Those persons interested in further information on the topic of Asian lacquer can click on the "Publications" tab near the top of the page, which suggests two authoritative books on lacquer. Still more information can be found on the Victoria and Albert Museum website, accessible by the links in the "Learn More" box on the far right hand side of the homepage.

27

Phytochemical, antioxidant and protective effect of Rhus tripartitum root bark extract against ethanol-induced ulcer in rats.  

PubMed

Rhus tripartitum (sumac) is an Anacardiaceae tree with a wide phytotherapeutic application including the use of its roots in the management of gastric ulcer. In the present study the Rhus tripartitum root barks extract (RTE) was phytochemical studied, in vitro tested for their potential antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power assay and in vivo evaluated for its ability to prevent ethanol-induced gastric ulcer in rats. The RTE was rich in phenolics, flavonoids, tannins and polysaccharide contents and exhibited a low but not weak in vitro antioxidant activity when compared with (+)-catechin. Pre-treatment with RTE at oral doses 50, 200 and 400 mg/kg body weight was found to provide a dose-dependent protection against ethanol-induced ulcer by averting the deep ulcer lesions of the gastric epithelium, by reducing gastric juice and acid output, by enhancing gastric mucus production by preserving normal antioxidant enzymes activities, and inhibiting the lipid peroxidation. The antiulcerogenic activity of RTE might be due to a possible synergistic antioxidant and antisecretory effects. PMID:23531841

Alimi, Hichem; Mbarki, Sakhria; Barka, Zeineb B; Feriani, Anwer; Bouoni, Zouhour; Hfaeidh, Najla; Sakly, Mohsen; Tebourbi, Olfa; Rhouma, Khémais B

2013-03-01

28

Biological activities of extracts from sumac (Rhus spp.): a review.  

PubMed

Sumac is the common name for a genus (Rhus) that contains over 250 individual species of flowering plants in the family Anacardiaceae. These plants are found in temperate and tropical regions worldwide, often grow in areas of marginal agricultural capacity, and have a long history of use by indigenous people for medicinal and other uses. The research efforts on sumac extracts to date indicate a promising potential for this plant family to provide renewable bioproducts with the following reported desirable bioactivities: antifibrogenic, antifungal, antiinflammatory, antimalarial, antimicrobial, antimutagenic, antioxidant, antithrombin, antitumorigenic, antiviral, cytotoxic, hypoglycaemic, and leukopenic. As well, the bioactive components can be extracted from the plant material using environmentally benign solvents that allow for both food and industrial end-uses. The favorable worldwide distribution of sumac also suggests that desirable bioproducts may be obtained at the source, with minimal transportation requirements from the source through processing to the end consumer. However, previous work has focussed in just a few members of this large plant family. In addition, not all of the species studied to date have been fully characterized for potential bioactive components and bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better understand the full potential of the Rhus genus as part of global green technology based on bioproducts and bioprocesses research programs. PMID:17909971

Rayne, Sierra; Mazza, G

2007-12-01

29

Atomic Oxygen Removes Varnish And Lacquer From Old Paintings  

NASA Technical Reports Server (NTRS)

Dry and relatively nondestructive plasma process found effective in removing protective coats from old paintings. Process generates monatomic oxygen, which reacts with varnish, lacquer, polyurethane, acrylic, and other organic coating materials; reactions produce mostly carbon monoxide and water vapor, then simply pumped away by vacuum system in which plasma generated. Does not attack oxide-based pigments in underlying paint layers, and brush-stroke marks remain undisturbed.

Rutledge, Sharon K.; Banks, Bruce A.; Cales, Michael

1996-01-01

30

Rhus chinensis and Galla Chinensis--folklore to modern evidence: review.  

PubMed

The species Rhus chinensis Mill. (Anacardiaceae) is an important representative of the genus Rhus, which contains over 250 individual species found in temperate and tropical regions worldwide. Rhus chinensis has long been used by folk medicine practitioners in Asia. Leaves, roots, stem, bark, fruit and particularly the galls on Rhus chinensis leaves, Galla chinensis, are recognized to have preventative and therapeutic effects on different ailments (such as diarrhea, dysentery, rectal and intestinal cancer, diabetes mellitus, sepsis, oral diseases and inflammation). However, it is critical to separate evidence from anecdote. Fortunately, recent scientific research has revealed that Rhus chinensis compounds possess strong antiviral, antibacterial, anticancer, hepatoprotective, antidiarrheal and antioxidant activities. Moreover, compounds isolated from the stem of Rhus chinensis significantly suppressed HIV-1 activity in vitro. Compounds from this plant were also found to inhibit enamel demineralization in vitro and enhance remineralization of dental enamel with fluoride. This review highlights claims from traditional and tribal medicinal lore and makes a contemporary summary of phytochemical, biological and pharmacological findings on this plant material. It aims to show that the pharmaceutical potential of this plant deserves closer attention. PMID:20564459

Djakpo, Odilon; Yao, Weirong

2010-12-01

31

Influences of heat seal lacquer thickness on the quality of blister packages.  

PubMed

A sealability of aluminium lidding foils against formable polymer materials of blister packages is usually achieved by a coating of aluminium with certain grammages of heat seal lacquers. To investigate influences of their thickness on quality of blister packages, lidding foils with different grammages of two lacquer types were manufactured. Sealing experiments (variation of temperature, pressure and sealing time) were performed. Sealed seam strengths were determined with mechanical tensile tests, tightness of cold form blisters were analysed by means of helium leakage tests. Time-dependent moisture uptake of stored blisters was monitored with micro-gas chromatography. By means of a simple calculation model the permeability coefficients of the heat seal lacquers were determined. Lidding foils with higher lacquer grammages showed significantly greater sealed seam strengths. Helium leakage tests showed only slight effects of heat seal lacquer grammage on tightness of blisters. But cold form blisters with lidding foils of higher lacquer grammages showed a significantly greater moisture uptake. Since the heat seal lacquers and the rigid polyvinyl chloride of the formable aluminium compound foils had similar permeability coefficients, the contribution of the lacquers to the total permeability of the investigated cold form blisters was only slightly. PMID:22108348

Mühlfeld, Lukas; Langguth, Peter; Häusler, Heribert; Hagels, Hansjörg

2012-01-23

32

Inflammatory and genotoxic effects of sanding dust generated from nanoparticle-containing paints and lacquers.  

PubMed

Nanoparticles are increasingly used in paints and lacquers. Little is known of the toxicity of nanoparticles incorporated in complex matrices and released during different phases of the life cycle. DNA damaging activity and inflammogenicity of sanding dust sampled during standardised sanding of boards painted with paints with and without nanoparticles were determined 24 h after intratracheal instillation of a single dose of 54 ?g in mice. Dusts from nanoparticle-containing paints and lacquers did not generate pulmonary inflammation or oxidative stress. Sanding dust from both the nanoparticle-containing and the conventional lacquer and the outdoor acrylic-based reference paint increased the level of DNA strand breaks in bronchoalveolar fluid cells. In conclusion, addition of nanoparticles to paint or lacquers did not increase the potential of sanding dust for causing inflammation, oxidative stress or DNA damage, suggesting that the paint/lacquer matrix is more important as determinant of DNA damage than the nanomaterial. PMID:21995293

Saber, Anne Thoustrup; Koponen, Ismo Kalevi; Jensen, Keld Alstrup; Jacobsen, Nicklas Raun; Mikkelsen, Lone; Møller, Peter; Loft, Steffen; Vogel, Ulla; Wallin, Håkan

2012-11-01

33

Formulation of non-lacquer (latex) PBX-9502  

SciTech Connect

Waste minimization necessitates evaluation of current waste streams with regard to new processing methods and technology. PBX-9502 (95% TATB/5% Kel-F 800) uses an ethyl acetate solvent to dissolve the Kel-F 800 resin, creating a lacquer for coating TATB. This report describes a new latex polymer application method for PBX-9502, which eliminates the H{sub 2}O-to-ethyl acetate rinse-out and the resultant solvent-contaminated water waste stream and distillation air emissions.

Sadler, C.P.; Freer, J.E.

1995-06-01

34

Bioactive constituents from Harpephyllum caffrum Bernh. and Rhus coriaria L  

PubMed Central

Background: The leaf ethanol extract of Harpephyllum caffrum Bernh. has evidenced medicinal value due to its hepatoprotective activity. It demonstrated inhibitory effects on test standard microbes approximated to 40% the potency of ofloxacin and fluconazole. The same extract evidenced in vitro cytotoxicity on human cell lines, liver carcinoma HEPG2, larynx carcinoma HEP2, and colon carcinoma HCT116 cell lines when compared to doxorubicin. Materials and Methods: Fractionation of the leaf ethanol extract led to the isolation of the polyphenols, ethyl gallate, and quercetin-3-O-rhamnoside, a hydrocarbon, hendecane, the fatty acid ester, methyl linoleate, and four triterpenoids, betulonic acid, 3-acetyl-methyl betulinate, lupenone and lupeol for the first time, in addition to the previously reported phenol acids and flavonoids, gallic acid, methyl gallate, quercetin, kaempferol, kaempferol-3-O-rhamnoside, kaempferol-3-O-galactoside, apigenin-7-O-glucoside, and quercetin-3-O-arabinoside. Results: The ethanol extract of the fruit of the genetically related Rhus coriaria L., known as sumac, afforded protocatechuic acid, isoquercitrin, and myricetin-3-O-?-L-rhamnoside from the fruits for the first time, in addition to the previously reported phenol acids and flavonoids, gallic acid, methyl gallate, kaempferol, and quercetin. Conclusion: The leaf ethanol extract of H. caffrum Bernh. exhibited variable anti-inflammatory, analgesic, and antipyretic activities, besides the hepatoprotective, in vitro cytotoxic and anti-microbial activities.

Shabana, Marawan M.; El Sayed, Aly M.; Yousif, Miriam F.; El Sayed, Abeer M.; Sleem, Amany A.

2011-01-01

35

Chrome-free corrosion protective coating based on lacquer hybridized with silicate  

Microsoft Academic Search

A lacquer sap hybridized with a silicate oligomer was synthesized, and its characteristics as a chrome-free corrosion protective coating were examined. A new absorption due to a siloxane structure appeared at 6.6ppm in the NMR and at 1080 and 840cm?1 in the IR spectra. The hybrid lacquer dries faster due to the reaction between the alkoxy radical of the silicate

Takayuki Honda; Rong Lu; Tetsuo Miyakoshi

2006-01-01

36

Development of microwave absorbing materials prepared from a polymer binder including Japanese lacquer and epoxy resin  

NASA Astrophysics Data System (ADS)

Microwave absorption composites were synthesized from a poly urushiol epoxy resin (PUE) mixed with one of microwave absorbing materials; Ni-Zn ferrite, Soot, Black lead, and carbon nano tube (CNT) to investigate their microwave absorption properties. PUE binders were specially made from Japanese lacquer and epoxy resin, where Japanese lacquer has been traditionally used for bond and paint because it has excellent beauty. Japanese lacquer solidifies with oxygen contained in air's moisture, which has difficulty in making composite, but we improved Japanese lacquer's solidification properties by use of epoxy resin. We made 10 mm thickness composite samples and cut them into toroidal shape to measure permittivity, permeability, and reflection loss in frequencies ranging from 50 Hz to 20 GHz. Electric magnetic absorber's composites synthesized from a PUE binders mixed either with Soot or CNT showed significantly higher wave absorption over -27 dB than the others at frequencies around 18 GHz, although Japanese lacquer itself doesn’t affect absorption. This means Japanese lacquer can be used as binder materials for microwave absorbers.

Iwamaru, T.; Katsumata, H.; Uekusa, S.; Ooyagi, H.; Ishimura, T.; Miyakoshi, T.

37

Separation of lacquer polysaccharides and interaction with poly-L-lysine.  

PubMed

A naturally occurring acidic lacquer polysaccharide with glucuronic acid at the terminals of the complex branches has specific biological activities including promotion of blood coagulation and antitumor activities. The polysaccharide has two molecular weight fractions M¯n=10×10(4) and M¯n=3.0×10(4). In the present work, two pure fractions were isolated for the first time by Sephadex G-100 column chromatography. Then, each fraction was treated with diluted alkaline solution to decrease the molecular weights to M¯n=3.0×10(4) and M¯n=1.4×10(4), respectively. The NMR and IR spectra and specific rotations of the fractionated and original lacquer polysaccharides were almost identical, suggesting that the lacquer polysaccharides are an associated structure with several low molecular weight polysaccharides of M¯n=1.4×10(4). Interactions between each lacquer polysaccharide and poly-L-lysine, a model compound of proteins and peptides with positively-charged amino groups, were investigated by surface plasmon resonance (SPR) to elucidate the biological mechanism. The apparent dissociation-rate (kd), association-rate (ka), and dissociation constant (KD) obtained by SPR indicate that the lacquer polysaccharides had weaker interactions with poly-L-lysine than sulfated polysaccharides and that the interaction depended on the molecular weight. These SPR results suggest that the specific biological activities of lacquer polysaccharides originate from electrostatic interaction. PMID:23987344

Bai, Yuting; Yoshida, Takashi

2013-10-15

38

A Leaflet of Rhus toxicodendroides, a Fossil Plant from the Los Ahuehuetes Locality, Puebla, Mexico  

NSDL National Science Digital Library

A leaflet of Rhus toxicodendroides, a fossil plant from the Los Ahuehuetes locality, Puebla, Mexico, a center of diversity for the Anacardiaceae since the Oligocene, suggesting that the area was important for the radiation and diversification for some lineages within the family.

Hector Hernández Campos

2004-03-09

39

A search for hepatoprotective activity of aqueous extract of Rhus coriaria L. against oxidative stress cytotoxicity.  

PubMed

The protective effects of different concentrations of aqueous extract of Rhus coriaria L. fruit (75 and 100 microg/ml) and also gallic acid (100 microM) as one of its main components were examined against oxidative stress toxicity induced by cumene hydroperoxide (CHP) in isolated rat hepatocytes. Both extract concentrations and gallic acid (100 microM) significantly (P<0.05) protected the hepatocyte against all oxidative stress markers including cell lysis, ROS generation, lipid peroxidation, glutathione depletion, mitochondrial membrane potential decrease, lysosomal membrane oxidative damage and cellular proteolysis. Aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) were more effective than gallic acid (100 microM) in protecting hepatocytes against CHP induced lipid peroxidation (P<0.05). On the other hand gallic acid (100 microM) acted more effective than aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) at preventing hepatocyte membrane lysis (P<0.05). In addition H(2)O(2) scavenging effect of both extract concentrations (75 and 100 microg/ml) were determined in hepatocytes and compared with gallic acid (100 microM). Gallic acid (100 microM) was more effective than aqueous extracts of Rhus coriaria L. (75 and 100 microg/ml) at H(2)O(2) scavenging activity (P<0.05). PMID:20036300

Pourahmad, Jalal; Eskandari, Mohammad Reza; Shakibaei, Rashin; Kamalinejad, Mohammad

2010-03-01

40

The Influence of a Liquid Medium on the Service Life and the Friction Coefficients of Lubricating Lacquers Based on Molybdenum Disulfide.  

National Technical Information Service (NTIS)

The practicality of simultaneously using lubricating lacquers and a liquid lubricant was investigated. Water and oil (viscosity at 50 degrees 4.2 centistokes) were used as liquid phases. The lubricating lacquers were mixed with such adhesives as polysilox...

L. N. Sentyurichina E. M. Oparina V. A. Listov

1969-01-01

41

Ciclopirox nail lacquer for the treatment of onychomycosis: an open non-comparative study.  

PubMed

Onychomycosis is a relatively common disease accounting for up to 50% of all nail disorders. Topical treatment, although less effective than systemic, is usually preferred by patients. Topical antifungal nail lacquers have been formulated to provide better delivery of the antifungal agent to the nail unit. The purpose of this research is to evaluate the efficacy and safety of ciclopirox nail lacquer in the treatment of onychomycosis. Patients suffering from distal and lateral subungual toenail onychomycosis (DLSO) and lateral subungual onychomycosis (LSO) were treated by ciclopirox nail lacquer once daily for 9 months. Every week the nail lacquer was removed using acetone. Clinical nail status, KOH examination and mycological culture were recorded by the same investigator at 0, 3, 6 and 9 months. Thirty-six patients completed the 9-month regimen. Trichophyton rubrum was the most common pathogen. At the end of the study, good improvement to complete cure was observed in 13 patients (36%), 12 patients showed only mild to moderate improvement and 11 patients (31%) had no clinical improvement. No adverse effects were noted throughout the treatment period. Ciclopirox nail lacquer seems to be slightly more effective than other topical modalities and could be used in patients who cannot or do not want systemic treatment. PMID:20175847

Shemer, Avner; Nathansohn, Nir; Trau, Henri; Amichai, Boaz; Grunwald, Marcelo H

2010-02-01

42

Dermatopharmacology of ciclopirox nail lacquer topical solution 8% in the treatment of onychomycosis.  

PubMed

Ciclopirox is a synthetic hydroxypyridone antifungal agent. In contrast to the azoles, glucuronidation is the main metabolic pathway of ciclopirox; therefore interactions with drugs metabolized via the cytochrome P450 system are unlikely Ciclopirox is also distinct from the common systemic agents, which interfere with sterol biosynthesis. In fact, ciclopirox chelates trivalent cations (such as Fe3+), inhibits metal-dependent enzymes that are responsible for degradation of toxic metabolites in the fungal cells, and targets diverse metabolic (eg, respiratory) and energy producing processes in microbial cells. Ciclopirox is a broad spectrum antimicrobial with activity against all the usual dermatophytes as well as yeast and nondermatophyte molds. It has demonstrated activity against gram positive and negative bacteria, including resistant strains of Staphlococcus aureus. Ciclopirox exhibits fungal inhibitory activity (minimum inhibitory concentration < 4 microg/mL for dermatophytes) as well as fungicidal activity; to date resistance to the drug has not been identified. Ciclopirox has been formulated in a nail lacquer delivery system. After evaporation of volatile solvents in the lacquer, the concentration of ciclopirox in the remaining lacquer film reaches approximately 35%, providing a high concentration gradient for penetration into the nail. Radiolabel data demonstrate penetration into infected nails after only 1 application of the lacquer. Ciclopirox nail lacquer is a topical product that provides an active fungicidal agent in a delivery system capable of promoting nail penetration. With repeated applications, the antifungal agent is homogeneously distributed through all layers of the toenail achieving concentrations of ciclopirox in excess of inhibitory and fungicidal concentrations for most pathogens. Although ciclopirox readily penetrates nails, very low levels of ciclopirox are recoverable systemically, even after chronic use. Ciclopirox nail lacquer 8% is a topical product that provides an active fungicidal agent in a delivery system capable of penetrating nails. PMID:11051135

Bohn, M; Kraemer, K T

2000-10-01

43

Ciclopirox nail lacquer 8% for the treatment of onychomycosis: a Canadian perspective.  

PubMed

Onychomycosis is prevalent in the Canadian population, and risk factors, such as old age and diabetes, are increasing. This condition has traditionally been treated using oral antifungal agents with varying degrees of success. Recently, ciclopirox nail lacquer 8% solution became the first topical agent approved in Canada for onychomycosis. Ciclopirox nail lacquer may be safe and effective for the treatment of onychomycosis, and certain candidates may benefit from therapy. Ciclopirox may be implicated for prophylactic use in order to prevent recurrent infection and may be used in combination with oral agents. PMID:16292454

Gupta, A K; Schouten, J R; Lynch, L E

2005-09-01

44

Integrating Traditional Medicine into Modern Inflammatory Diseases Care: Multitargeting by Rhus verniciflua Stokes  

PubMed Central

Despite the fact that numerous researches were performed on prevention and treatment of inflammation related diseases, the overall incidence has not changed remarkably. This requires new approaches to overcome inflammation mediated diseases, and thus traditional medicine could be an efficacious source for prevention and treatment of these diseases. In this review, we discuss the contribution of traditional medicine, especially Rhus verniciflua Stokes, to modern medicine against diverse inflammation mediated diseases. Traditionally, this remedy has been used in Eastern Asia for the treatment of gastric problems, hepatic disorders, infectious diseases, and blood disorders. Modern science has provided the scientific basis for the use of Rhus verniciflua Stokes against such disorders and diseases. Various chemical constituents have been identified from this plant, including phenolic acid, and flavonoids. Cell-based studies have exhibited the potential of this as antibacterial, antioxidant, neuroprotective, anti-inflammatory, growth inhibitory, and anticancer activities. Enormous animal studies have shown the potential of this against proinflammatory diseases, neurodegenerative diseases, diabetes, liver diseases, and chemical insults. At the molecular level, this medicinal plant has been shown to modulate diverse cell-signaling pathways. In clinical studies, Rhus verniciflua Stokes has shown efficacy against various cancer patients such as colorectal, gastric, hepatic, renal, pancreatic, and pulmonary cancers. Thus, this remedy is now exhibiting activities in the clinic.

Kim, Ji Hye; Shin, Yong Cheol; Ko, Seong-Gyu

2014-01-01

45

Synthesis and properties of a lacquer wax-based quarternary ammonium gemini surfactant.  

PubMed

Lacquer wax is an important fatty resource obtained from the mesocarp of the berries of Toxicodendron vernicifluum. In order to expand the applications of lacquer wax, we hydrolyzed it after establishing the best conditions for the acid-catalyzed hydrolysis using a Box-Behnken design. Then we synthesized a quarternary ammonium gemini surfactant by a three-step reaction. The surface properties of an aqueous solution of the final product were investigated. The optimum conditions were 9% catalyst, 100 °C of reaction temperature and 14 h of reaction time, while the maximum free fatty acids (FFA)% was 99.67%. From the gas chromatography, the main fatty acids of the lacquer wax were palmitic, oleic and octadecanoic acid. The lacquer wax gemini surfactant was synthesized, and its structure was confirmed by IR and NMR. The experiments showed that the critical micelle concentration (CMC) is 5 × 10?? mol·L?¹, the surface tension is 33.6 mN·m?¹. When the content of surfactant was 0.1%, the separation time of 5 mL water was 10 min. PMID:24662075

Chen, Hongxia; Wang, Chengzhang; Ye, Jianzhong; Zhou, Hao; Lu, Li; Yang, Zhibing

2014-01-01

46

Toxic leukoencephalopathy with atypical MRI features following a lacquer thinner fire.  

PubMed

Toxic leukoencephalopathy is a structural alteration of the white matter following exposure to various toxic agents. We report a 49-year-old man exposed to an explosion of lacquer thinner with brain MRI features atypical from those of chronic toxic solvent intoxication. PMID:24291481

Kao, Hung-Wen; Pare, Laura; Kim, Ronald; Hasso, Anton N

2014-05-01

47

Ciclopirox 8% nail lacquer in the treatment of onychomycosis of the toenails in the United States.  

PubMed

Ciclopirox 8% nail lacquer has recently become the first topical antifungal agent to be approved by the US Food and Drug Administration for the treatment of onychomycosis. This article reviews the results of the two pivotal clinical trials of this drug that have been performed in the United States as well as those that have been carried out in other countries. The two US studies were both double-blind, vehicle-controlled, parallel-group, multicenter studies designed to determine the efficacy and safety of ciclopirox nail lacquer in the treatment of mild-to-moderate onychomycosis of the toenails caused by dermatophytes. The combined results show a 34% mycologic cure rate, as compared with 10% for the placebo. Data from the ten studies conducted worldwide show a meta-analytic mean (+/- SE) mycologic cure rate of 52.6% +/- 4.2%. As expected for a topical agent, ciclopirox nail lacquer was found to be extremely safe, with mild, transient irritation at the site of application reported as the most common adverse event. Ciclopirox nail lacquer may also have potential for use in combination or adjunctive therapy. Further studies will help to better position this agent for the treatment of this widespread podiatric condition. PMID:11107710

Gupta, A K; Joseph, W S

2000-01-01

48

Imaging Stokes polarimeter by dual rotating retarder and analyzer and its application of evaluation of Japanese lacquer  

NASA Astrophysics Data System (ADS)

Lacquer crafts are distributed over Southeast Asia from the East Asia such as China and Korea, Vietnam, Myanmar including Japan. Especially, a Japanese lacquer is well-known traditional crafts. Its color is jet black but people feel different texture because it is made by complicated and multi step manufacturing process such as coating and polishing with different materials. In this report, we focus polarization properties of surface structures on black Japanese lacquer. All states of polarization can be expressed Stokes parameters, which are consisted on four elements as s0 to s3. These parameters are effective for the evaluation of the state of polarization. The polarization information of surface structure of Japanese lacquer can be visualized by using an imaging Stokes polarimeter by dual rotating retarder and analyzer. It is possible to evaluate surface character by comparing the degree of polarization. It is effective to evaluate the surface by using the polarization information.

Mizutani, Ryota; Ishikawa, Tomoharu; Ayama, Miyoshi; Otani, Yukitoshi

2012-11-01

49

Polypyrrole\\/poly(methylmethacrylate) blend as selective sensor for acetone in lacquer  

Microsoft Academic Search

A film of ?-naphthalene sulfonate-doped polypyrrole\\/poly(methylmethacrylate), PPy\\/?-NS?\\/PMMA, obtained from solution mixing was successfully used as sensing material for acetone vapor in lacquer with a high degree of selectivity based on electrical conductivity over acetic acid and a high degree of stability over the humidity change. Compared with pure PPy\\/?-NS?, the selectivity ratio of acetone\\/acetic acid response of PPy\\/?-NS?\\/PMMA blend with

Ladawan Ruangchuay; Anuvat Sirivat; Johannes Schwank

2003-01-01

50

Analysis of organic compounds in a case of suicide by ignition with lacquer thinner.  

PubMed

An autopsy case of suicide by ignition using lacquer thinner is presented. A wholly-charred body of a 54-year-old man and a can of lacquer thinner were found at the burnt driver's seat of a truck. Organic solvents in blood, urine, lung tissue, trachea and gastric contents and of the remaining clothes have been analyzed by gas chromatography/mass spectrometry (GC/MS). High levels of toluene, ethyl acetate and butyl acetate were detected in his clothes. The concentrations of toluene in the left and right heart blood, urine, gastric contents, squeeze sample and a block of lung tissue were 0.309, 0.226, 0.018, 0.051, and 0.268 mg/ml, and 0.340 mg/g, respectively. The ethanol levels in these samples were 1.89, 1.71, 1.58, 13.88 and 1.39 mg/ml, and 1.49 mg/g, respectively, and the profile suggested that the source of the ethanol was mainly drinking. The carboxyhemoglobin concentration in the left and right heart blood was 43.3 and 36.1%, respectively. The GC/MS data on organic solvents are consistent with the idea that he used the lacquer thinner contained in the can found in his truck for ignition. The high levels of toluene in his blood suggest that not only burns but also toluene poisoning contributed to his death. PMID:8583691

Yoshida, M; Akane, A; Okii, Y; Yoshimura, S; Tokiyasu, T; Watabiki, T

1995-12-01

51

Natural coniferous resin lacquer in treatment of toenail onychomycosis: an observational study  

PubMed Central

In in vitro tests, natural coniferous resin from the Norway spruce (Picea abies) is strongly antifungal. In this observational study, we tested the clinical effectiveness of a lacquer composed of spruce resin for topical treatment of onychomycosis. Thirty-seven patients with clinical diagnosis of onychomycosis were enrolled into the study. All patients used topical resin lacquer treatment daily for 9 months. A mycological culture and potassium hydroxide (KOH) stain were done from nail samples in the beginning and in the end of the study. Treatment was considered effective, if a mycological culture was negative and there was an apparent clinical cure. At study entry, 20 patients (20/37; 54%; 95% CI: 38–70) had a positive mycological culture and/or positive KOH stain for dermatophytes. At study end, the result of 13 patients was negative (13/19; 68%; 95% CI: 48–89). In one case (1/14; 7%; 95% CI: 0–21) the mycological culture was initially negative, but it turned positive during the study period. By 14 compliant patients (14/32; 44%; 95% CI: 27–61), resin lacquer treatment was considered clinically effective: complete healing took place in three cases (9%) and partial healing in 11 cases (85%). The results indicate some evidence of clinical efficacy of the natural coniferous resin used for topical treatment of onychomycosis.

Sipponen, Pentti; Sipponen, Arno; Lohi, Jouni; Soini, Marjo; Tapanainen, Riikka; Jokinen, Janne J

2013-01-01

52

Contradictory results of the UVCON and saline immersion tests regarding the evaluation of some inhibitor\\/lacquer combinations on galvanised coatings  

Microsoft Academic Search

The effectiveness of inhibitors “with chromate” and “with phosphate” that accompany lacquer films applied on hot galvanised steel specimens has been studied using continuous immersion tests in 3% NaCl and UVCON tests in a climate cabinet. These tests, in combination with the EIS and XPS techniques, show that the behaviour of the inhibitor\\/lacquer system is dependent on the type of

S Feliu; V Barranco

2004-01-01

53

In vitro antibacterial and antifungal activities of Rhus tripartitum used as antidiarrhoeal in Tunisian folk medicine.  

PubMed

Rhus tripartitum (African sumac) is a plant commonly used in Tunisian traditional medicine to treat diarrhoea and dysentery. In this study, we have demonstrated that R. tripartitum extracts exhibited a significant broad spectrum activity against one or more of the test microorganisms with a zone size ranging from 8 to 28?mm in diameter. These diameters are much higher than those obtained with standard antibiotics. The chloroformic extracts were found to be effective against bacterial and fungal strains tested, with MIC values ranging between 0.07 and 0.62?mg?mL(-1) against Staphylococcus aureus and Candida albicans. However, ethyl-acetate/methanol fractions showed a selective activity only against bacterial microorganisms with low MIC values between 0.07 and 0.15?mg?mL(-1). The overall results suggested that the traditional use of R. tripartitum for the treatment of diarrhoea tract infections was attributed to the presence of antibacterial agents. PMID:22132736

Abbassi, Feten; Hani, Khaled

2012-01-01

54

Rhus verniciflua stokes against advanced cancer: a perspective from the Korean Integrative Cancer Center.  

PubMed

Active anticancer molecules have been searched from natural products; many drugs were developed from either natural products or their derivatives following the conventional pharmaceutical paradigm of drug discovery. However, the advances in the knowledge of cancer biology have led to personalized medicine using molecular-targeted agents which create new paradigm. Clinical benefit is dependent on individual biomarker and overall survival is prolonged through cytostatic rather than cytotoxic effects to cancer cell. Therefore, a different approach is needed from the single lead compound screening model based on cytotoxicity. In our experience, the Rhus verniciflua stoke (RVS) extract traditionally used for cancer treatment is beneficial to some advanced cancer patients though it is herbal extract not single compound, and low cytotoxic in vitro. The standardized RVS extract's action mechanisms as well as clinical outcomes are reviewed here. We hope that these preliminary results would stimulate different investigation in natural products from conventional chemicals. PMID:22174564

Choi, Woncheol; Jung, Hyunsik; Kim, Kyungsuk; Lee, Sookyung; Yoon, Seongwoo; Park, Jaehyun; Kim, Sehyun; Cheon, Seongha; Eo, Wankyo; Lee, Sanghun

2012-01-01

55

Rhus verniciflua Stokes against Advanced Cancer: A Perspective from the Korean Integrative Cancer Center  

PubMed Central

Active anticancer molecules have been searched from natural products; many drugs were developed from either natural products or their derivatives following the conventional pharmaceutical paradigm of drug discovery. However, the advances in the knowledge of cancer biology have led to personalized medicine using molecular-targeted agents which create new paradigm. Clinical benefit is dependent on individual biomarker and overall survival is prolonged through cytostatic rather than cytotoxic effects to cancer cell. Therefore, a different approach is needed from the single lead compound screening model based on cytotoxicity. In our experience, the Rhus verniciflua stoke (RVS) extract traditionally used for cancer treatment is beneficial to some advanced cancer patients though it is herbal extract not single compound, and low cytotoxic in vitro. The standardized RVS extract's action mechanisms as well as clinical outcomes are reviewed here. We hope that these preliminary results would stimulate different investigation in natural products from conventional chemicals.

Choi, Woncheol; Jung, Hyunsik; Kim, Kyungsuk; Lee, Sookyung; Yoon, Seongwoo; Park, Jaehyun; Kim, Sehyun; Cheon, Seongha; Eo, Wankyo; Lee, Sanghun

2012-01-01

56

Potential neuroprotective flavonoid-based inhibitors of CDK5/p25 from Rhus parviflora.  

PubMed

Rhus parviflora (Anacardiaceae) is an indigenous medicinal shrub found in South Asia with flavonoid rich edible fruit. This study examined flavonoid derivatives of R. parviflora fruit with CDK5/p25 inhibition activity. Evaluation by in vitro assay and docking simulations for CDK5/p25 revealed that the aurones, sulfuretin (1) and aureusidin (2), the aurone glycoside, aureusidin-6-O-?-D-glucopyranoside (3) and hovetrichoside C (4), the flavonoid glycoside, quercetin-3-O-?-D-galactopyranoside (5), and the biflavonoid, cupressuflavone (6), had the potential to inhibit CDK5/p25, which could be useful in the treatment of neurodegenerative disorders such as Alzheimer's disease. Compound2 showed the significant in vitro inhibition capacity (IC50 value of 4.81 ?M) as well as binding affinity with docking energy of -8.73 (kcal/mol) for active sites CYS83 and GLN130 of CDK5/p25 enzyme in comparison to reference compound R-roscovitine. PMID:23927974

Shrestha, Sabina; Natarajan, Sathishkumar; Park, Ji-Hae; Lee, Dae-Young; Cho, Jin-Gyeong; Kim, Geum-Soog; Jeon, Yong-Jin; Yeon, Seung-Woo; Yang, Deok-Chun; Baek, Nam-In

2013-09-15

57

HPLC-DAD-ESI-MS/MS screening of bioactive components from Rhus coriaria L. (Sumac) fruits.  

PubMed

Rhus coriaria L. (sumac) is an important crop widely used in the Mediterranean basin as a food spice, and also in folk medicine, due to its health-promoting properties. Phytochemicals present in plant foods are in part responsible for these consequent health benefits. Nevertheless, detailed information on these bioactive compounds is still scarce. Therefore, the present work was aimed at investigating the phytochemical components of sumac fruit epicarp using HPLC-DAD-ESI-MS/MS in two different ionisation modes. The proposed method provided tentative identification of 211 phenolic and other phyto-constituents, most of which have not been described so far in R. coriaria fruits. More than 180 phytochemicals (tannins, (iso)flavonoids, terpenoids, etc.) are reported herein in sumac fruits for the first time. The obtained results highlight the importance of R. coriaria as a promising source of functional ingredients, and boost its potential use in the food and nutraceutical industries. PMID:25053044

Abu-Reidah, Ibrahim M; Ali-Shtayeh, Mohammed S; Jamous, Rana M; Arráez-Román, David; Segura-Carretero, Antonio

2015-01-01

58

Successful treatment of onychomycosis with ciclopirox nail lacquer: a case report.  

PubMed

Onychomycosis commonly causes patients to seek medical care. Its unpleasant cosmetic appearance and negative impact on a patient's quality of life often prompt these visits. Onychomycosis rarely resolves spontaneously and has a high rate of recurrence. Although a variety of treatment options are available, inconsistent results and poor patient compliance have often hindered their success. We report the case of a 75-year-old man with moderate-to-severe onychomycosis who was treated successfully with ciclopirox nail lacquer solution 8%, the first topical antifungal agent approved by the Food and Drug Administration for the treatment of this disease. PMID:11665725

Galitz, J

2001-08-01

59

Polymer films releasing nisin and\\/or natamycin from polyvinyldichloride lacquer coating: Nisin and natamycin migration, efficiency in cheese packaging  

Microsoft Academic Search

Polyethylene films coated by commercially available polyvinyldichloride (PVdC) as well as nitrocellulose (NC) lacquer with addition of natamycin preparation Delvocid® (16.7% w\\/w of natamycin in lacquer) were studied at 6 and 23°C to determine the preservative migration into distilled water. The films released natamycin at maximal level 2.34±0.32mg\\/dm2. The diffusion coefficient of 0.79×10?10±0.29×10?10cm2\\/s and 1.03×10?10±0.17×10?10cm2\\/s was determined for natamycin transport

Kristýna Hanušová; Monika Š?astná; Lenka Votavová; Kamila Klaudisová; Jaroslav Dobiáš; Michal Vold?ich; Miroslav Marek

2010-01-01

60

The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts  

Microsoft Academic Search

BACKGROUND: Butein (3,4,2',4'-tetrahydroxychalone), a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the

Michael Samoszuk; Jenny Tan; Guillaume Chorn

2005-01-01

61

Influence of between-year variation in the density of Rhus trichocarpa fruits on the removal of fruit by birds  

Microsoft Academic Search

The fruiting phenology and fruit removal patterns of Rhus trichocarpa Miq. (Anacardiaceae) were investigated in a warm-temperate secondary forest in Japan. Mature fruits of this species are dispersed by birds. Effects of fruit display size and canopy openness on fruit removal were investigated in years with different fruit densities (i.e., masting and non-masting years). Moreover, effects of increased canopy openness

Noriyuki Osada

2005-01-01

62

In vitro transungual permeation of ciclopirox from a hydroxypropyl chitosan-based, water-soluble nail lacquer.  

PubMed

Commercial antimycotic nail lacquers are commonly based on water-insoluble resins. The present study was aimed at evaluating a novel, experimental nail lacquer (P-3051, Polichem SA, Lugano, Switzerland) based on the water-soluble film-forming agent hydroxypropyl chitosan (HPCH). The in vitro permeation of ciclopirox (CPX) from P-3051 and from a commercial, water-insoluble lacquer based on a vinyl resin (Penlac, Aventis Pharma), was investigated using thin membranes obtained from bovine hooves, an accepted model for human nails. Similar CPX permeation fluxes at steady state through the membranes, but significantly different lag times were observed for P-3051 and Penlac, when these were tested as dry films. The formulations thus appeared to influence only the time required by CPX to saturate the membrane, and not the final drug concentration gradient in the membrane. Permeation experiments performed on the same membranes and on hairless mouse skin with P-3051 and with a similar, HPCH-free vehicle (ERV), both tested in liquid form, disproved the possibility that HPCH might act as a permeation enhancer for CPX in either substrate. The possible reasons for the greater efficiency of the HPCH vehicle in terms of CPX transfer from the vehicle itself to the keratin membrane are discussed. This effect might be tentatively attributed to a particular affinity of HPCH for the membrane, resulting in intimate contact and strong adhesion of the HPCH lacquer to the keratin substrate. PMID:15704853

Monti, Daniela; Saccomani, L; Chetoni, P; Burgalassi, S; Saettone, M F; Mailland, F

2005-01-01

63

A new benzofuranone and anti-HIV constituents from the stems of Rhus chinensis.  

PubMed

A new benzofuran lactone, rhuscholide A (1), was isolated from the stems of RHUS CHINENSIS, together with six known compounds: 5-hydroxy-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3 H)-benzofuranone (2), betulin (3), betulonic acid (4), moronic acid (5), 3-oxo-6 beta-hydroxyolean-12-en-28-oic acid (6) and 3-oxo-6 beta-hydroxyolean-18-en-28-oic acid (7). Based on 1D, 2D NMR (COSY, HMQC, HMBC) and mass (EI-MS, HR-EI-MS) spectral data, the structure of rhuscholide A was deduced to be 5-hydroxy-3-(propan-2-ylidene)-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3 H)-benzofuranone (1). Anti-HIV-1 bioassays IN VITRO revealed that compound 1 possesses significant anti-HIV-1 activity with an EC50 value of 1.62 microM and a therapeutic index (TI) of 42.40. Compounds 2, 4, 5 and 7 showed moderate anti-HIV-1 activities with EC50 values of 3.70, 5.81, 7.49 and 13.11 microM, respectively. PMID:17290322

Gu, Qiong; Wang, Rui-Rui; Zhang, Xue-Mei; Wang, Yun-Hua; Zheng, Yong-Tang; Zhou, Jun; Chen, Ji-Jun

2007-03-01

64

Phenolic extracts from Rhus verniciflua Stokes bark by decompressing inner ebullition and their antioxidant activities.  

PubMed

Decompressing inner ebullition (DIE) can reduce the extraction liquid boiling point and polyphenols oxidation in the extraction process. The aim of this study is to optimise the phenolic extraction process by DIE and to examine the antioxidant activities. The extraction process parameters were observed by central composite design. The antioxidant activity was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing power assays. The results showed that the optimal extraction condition is extract time of 90 min, temperature of 45°C, solid-liquid ratio of 1:20 g/mL, vacuum degree of - 0.08 MPa, ethanol concentration of 60%, while the phenolic content was 5.4%. The phenolic extracts from Rhus verniciflua Stokes bark had better antioxidant activities; the antioxidant activity (IC50) of the DIE was 20 ?g/mL by the DPPH method. The reducing power of the phenolic extracts was significantly related to their total phenolic content (R = 0.9903). The results presented show that the DIE method is an effective method for polyphenols extraction. PMID:24437977

Chen, Hongxia; Wang, Chengzhang; Ye, Jianzhong; Zhou, Hao; Yuan, Jiaojiao

2014-04-01

65

Antibacterial Activity of Rhus javanica against Methicillin-Resistant Staphylococcus aureus  

PubMed Central

In the present study, the leaves of Rhus javanica (R. javanica) were extracted with ethanol, and we investigated the antimicrobial activity of the ethanol extract of R. javanica against methicillin-resistant Staphylococcus aureus (MRSA). Control groups were treated with media containing 0.1% DMSO. The ethanol extract of R. javanica inhibited the growth of MRSA at concentrations ranging from 0.05 to 0.2?mg/mL and inhibited acid production at concentrations higher than 0.1?mg/mL (P < 0.05). MRSA biofilm formation was determined by scanning electron microscopy and safranin staining. The ethanol extract of R. javanica inhibited the formation of MRSA biofilms at concentrations higher than 0.05?mg/mL. In confocal laser scanning microscopy, high concentration (0.4–1.6?mg/mL) of R. javanica extract showed bactericidal effect in a dose-dependent manner. In real-time PCR analysis, R. javanica extract showed the inhibition of the genetic expression of virulence factors such as mecA, sea, agrA, and sarA in MRSA. Preliminary phytochemical analysis revealed the strong presence of phenolics. These results suggest that R. javanica may be a useful medicinal plant for inhibiting MRSA, which may be related to the presence of phenolics in the R. javanica extract.

You, Yong-Ouk; Kang, Sun-Young; Kim, Kang-Ju

2013-01-01

66

A multicenter, open-label study of the efficacy and safety of ciclopirox nail lacquer solution 8% for the treatment of onychomycosis in patients with diabetes.  

PubMed

This multicenter, open-label, uncontrolled, noncomparative, observational, postmarketing study assessed the efficacy and safety of ciclopirox nail lacquer solution 8% in 3666 patients for the treatment of onychomycosis. Results of an analysis in a subset of 215 (5.9%) patients with diabetes are summarized here. Patients applied ciclopirox nail lacquer once daily to affected toenails and fingernails for 6 months. Efficacy parameters included the decrease from baseline of the affected area of the nail. Physicians rated the level of onychomycosis at 3 months and the efficacy of ciclopirox nail lacquer at 6 months. Treatment with ciclopirox nail lacquer reduced the mean affected nail area from 64.3% at baseline to 41.2% at 3 months and 25.7% at 6 months. At 3 months, physicians rated onychomycosis as improved in 88.7% of patients. unchanged in 9.8%, and worse in 1.5%. The efficacy of ciclopirox nail lacquer was good in 62.0% of patients, satisfactory in 23.9%, and unsatisfactory in 14.1%. Adverse events were mild to moderate, with no serious events reported. Ciclopirox nail lacquer is safe and effective for the topical treatment of onychomycosis in patients with diabetes and produced results similar to those observed in the general population. PMID:11665724

Seebacher, C; Nietsch, K H; Ulbricht, H M

2001-08-01

67

Phytochemicals and antioxidant activities of Rhus tripartitum (Ucria) fruits depending on locality and different stages of maturity.  

PubMed

The phytochemical content (total phenolic compounds, total flavonoids, condensed tannins and phenolic composition) and the antioxidant potential of Rhus tripartitum fruits collected from different localities were screened during maturity. Significant variability was detected. HPLC analyses revealed the presence of 24 compounds with notable differences. Flavone and betulinic acid, which have numerous benefits, were the main detected compounds (more than 73%). This work highlights the importance of R. tripartitum fruits as dietary sources of natural antioxidants, and might be appropriate for the development of reliable index to estimate fruit richness with bioactive molecules. PMID:24799214

Tlili, Nizar; Mejri, Houda; Yahia, Yassine; Saadaoui, Ezzeddine; Rejeb, Saloua; Khaldi, Abdelhamid; Nasri, Nizar

2014-10-01

68

‘Safe sites’ for the seed germination of Rhus javanica : A characterization by responses to temperature and light  

Microsoft Academic Search

Germination responses ofRhus javanica L. seeds to temperature and light were investigated with special reference to their gap-detecting mechanisms in germination,\\u000a i.e., responses to elevated and\\/or fluctuating temperatures and sensitivity to leaf-canopy transmitted light. The seeds, which\\u000a have water-impermeable coats to prevent imbibition, were shown to become permeable and germinable after exposure to higher\\u000a temperatures of 48–74C for a brief

Izumi Washitani; Akio Takenaka

1986-01-01

69

Rhus coriaria ameliorates insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM) rats.  

PubMed

We have investigated the effect of methanolic extract of Rhus coriaria (RC) on hyperinsulinemia, glucose intolerance and insulin sensitivity in non-insulin-dependent diabetes mellitus (NIDDM) rats. NIDDM was induced by single intraperitoneal injection of streptozotocin (STZ, 100 mg/kg) to 2 days old rat pups. RC (200 mg/kg and 400 mg/kg) was administered orally once a day for 5 weeks after the animals were confirmed diabetic (i.e, 90 days after STZ injection). A group of citrate control rats were also maintained which has received citrate buffer on the 2nd day of their birth. There was a significant increase in blood glucose, glycosylated hemoglobin (HbA1c) and serum insulin levels were observed in NIDDM control rats. Treatment with RC reduced the elevated levels of blood glucose, HbA1c and insulin in the NIDDM rats. An oral glucose tolerance test (OGTT) was also performed in the same groups, in which we found a significant improvement in glucose tolerance in the rats treated with RC. The insulin sensitivity was assessed for both peripheral insulin resistance and hepatic insulin resistance. RC treatment significantly improved insulin sensitivity index (K(ITT)) which was significantly decreased in NIDDM control rats. There was significant rise in homeostasis model assessment of insulin resistance (HOMA-R) in NIDDM control rats whereas RC treatment significantly prevented the rise in HOMA-R in NIDDM treated rats. Our data suggest that methanolic extract of RC significantly delayed the onset of hyperinsulinemia and glucose intolerance and improved insulin sensitivity in NIDDM rats. PMID:24147364

Anwer, Tarique; Sharma, Manju; Khan, Gyas; Iqbal, Muzaffar; Ali, Mohammad Sajid; Alam, Mohammad Sarfaraz; Safhi, Mohammed Mohsen; Gupta, Nakul

2013-01-01

70

Polypyrrole and its composites with 3A zeolite and polyamide 6 as sensors for four chemicals in lacquer thinner  

Microsoft Academic Search

This work is an attempt to search for highly selective sensing elements for the chemical vapors in lacquer thinner. Chemically synthesized polypyrrole (PPy) and PPy composites with 3A zeolite (3A) and polyamide 6 (PA): i.e. PPy_3A50 pellet, PA20_PPy13_3A50 film, and PA20_PPy13_3A50 electrospun fiber bundle have been investigated as the sensing materials for four chemical vapors that are the common components

Ladawan Wannatong; Anuvat Sirivat

2008-01-01

71

The use of the Er:YAG 2940nm laser associated with amorolfine lacquer in the treatment of onychomycosis.  

PubMed

Onychomycosis is a common disease, accounting for up to 50% of all ungual pathologies. We have been developing a clinical trial (ClinicalTrials.gov: NCT01528813) using a 2940nm Er:YAG laser to fractionally ablate human nails in vivo, aiming to increase topical amorolfine lacquer delivery to the nail unit, increasing the efficacy of topical treatment of distal and lateral subungual onychomycosis. Partial results have shown an increase in areas of nail plate free of disease. We believe that ablative lasers can increase the efficacy of topical onychomycosis treatment. PMID:24173203

Morais, Orlando Oliveira de; Costa, Izelda Maria Carvalho; Gomes, Ciro Martins; Shinzato, Dayane Higa; Ayres, Guilherme Marreta Cavalcanti; Cardoso, Rayane Marques

2013-01-01

72

Ciclopirox nail lacquer 8%: in vivo penetration into and through nails and in vitro effect on pig skin.  

PubMed

This report presents original methods to assess the bioavailability of an antifungal drug from a varnish preparation in finger nails. For the studies with human volunteers a ciclopirox 8% nail lacquer was used to determine its efficacy in the treatment of onychomycoses. In vivo studies were performed on the fingernails of healthy volunteers by determining the total amount of ciclopirox penetrated per milligram of nail and the partition of the drug in the plate of the nails (technically divided into four layers). Ciclopirox concentrations were evaluated by measuring the inhibition of Candida pseudotropicalis growth in vitro. The ciclopirox concentration after 30 days treatment was determined as 3.35 +/- 0.82 micrograms/mg nail material. This is a sufficient amount to kill the fungal pathogens. In addition, in vitro penetration experiments were carried out with excised pig skin. Lacquer formulations from 0.5 to 8% were used to inhibit the growth of Trichophyton mentagrophytes. Formulations from 2 to 8% led to a strong to total inhibition of the dermatophyte after 30 min treatment time. PMID:1831626

Ceschin-Roques, C G; Hänel, H; Pruja-Bougaret, S M; Luc, J; Vandermander, J; Michel, G

1991-01-01

73

Antifungal activity, experimental infections and nail permeation of an innovative ciclopirox nail lacquer based on a water-soluble biopolymer.  

PubMed

P-3051 is an innovative 8% ciclopirox nail lacquer, based on hydroxypropyl chitosan (HPCH) as a film-forming agent. The authors' aim was to investigate P-3051's in vitro antifungal activity, as well as its in vitro and in vivo nail permeation. The dilution susceptibility tests performed for Trichophyton rubrum (T. rubrum) and Candida parapsilosis (C. parapsilosis) showed that the minimum inhibitory concentrations (MICs) of P-3051, as percent of ciclopirox, was for both fungi < or = 0.0015% (equivalent to a concentration of 15.6 mg/ ml). In the biological assay of in vitro nail permeation and fungal inhibition, the authors observed that P-3051 permeated well through bovine hoof membranes and produced dose-dependent inhibitory effects on dermatophyte, yeast and mold strains. Moreover, the inhibition effects were higher than those obtained by equal amounts of the ciclopirox reference nail lacquer. P-3051 and the reference showed the same protective activity in experimental infections with strains of dermatophytes isolated from clinical samples. The amount of ciclopirox remained in cut fingernails washed six hours after in vivo application of P-3051 ranged between 18 and 35% of the applied dose. After in vitro application to cut human nails, 40-50% of the applied ciclopirox penetrated during the first six hours, independent of nails being infected or uninfected, intact or filed. In both experiments, the concentration of ciclopirox is largely higher (three to four orders of magnitude) than the MICs for nail pathogens. PMID:20480796

Togni, Giuseppe; Mailland, Federico

2010-05-01

74

PROCESSING, PRODUCTS, AND FOOD SAFETY The Effect of Water Extract of Sumac (Rhus coriaria L.) and Lactic Acid on Decontamination and Shelf Life of Raw Broiler Wings  

Microsoft Academic Search

In an attempt to improve the bacteriologi- cal quality and refrigerated shelf life of broiler meat, 10- min surface wash treatments with sterile distilled water (DW), 8% (wt\\/vol) water extract of sumac (Rhus coriaria L.) fruits (WES), and 2% (vol\\/vol) lactic acid (LA) were compared by using a broiler wing model. The aerobic plate counts (log10 cfu\\/g) of psychrotrophs, mesophilic

M. Gulmez; N. Oral; L. Vatansever

75

Anti-inflammatory effects of sulfuretin from Rhus verniciflua Stokes via the induction of heme oxygenase-1 expression in murine macrophages  

Microsoft Academic Search

Rhus verniciflua Stokes (Anacardiaceae) has traditionally been used as an ingredient in East Asian medicines used to treat oxidative damage and cancer. Sulfuretin is one of the major flavonoid components isolated from R. verniciflua. In the present study, we isolated sulfuretin from R. verniciflua and demonstrated that sulfuretin inhibited inducible nitric oxide synthase (iNOS) protein and mRNA expression, reduced iNOS-derived

Dong-Sung Lee; Gil-Saeng Jeong; Bin Li; Hyun Park; Youn-Chul Kim

2010-01-01

76

Comparative EIS and XPS studies of the protective character of thin lacquer films containing CR or P salts formed on galvanised steel, galvanneal and galfan substrates  

Microsoft Academic Search

X-ray photoelectron spectroscopy (XPS) is used to analyse variations during exposure to humidity and UV radiation (UVCON test) in the chemical composition of the outer surface of organic coatings (lacquers) containing phosphating or chromating reagents applied on galvanised steel, galvanneal and galfan substrates. By means of electrochemical impedance spectroscopy (EIS) measurements the protective character of the coatings analysed by XPS

S Feliu; V Barranco

2004-01-01

77

Ultrasonic Extraction of Antioxidants from Chinese Sumac (Rhus typhina L.) Fruit Using Response Surface Methodology and Their Characterization.  

PubMed

For the first time, response surface methodology (RSM) using a Box-Behnken Design (BBD) was employed to optimize the conditions for ultrasonic assisted extraction (UAE) of antioxidants from Chinese sumac (Rhus typhina L.) fruits. Initially, influencing factors such as liquid-solid ratio, duration of ultrasonic assisted extraction, pH range, extraction temperature and ethanol concentration were identified using single-factor experiments. Then, with respect to the three most significant influencing factors, the extraction process focusing on the DPPH· scavenging capacity of antioxidants was optimized using RSM. Results showed that the optimal conditions for antioxidant extraction were 13.03:1 (mL/g) liquid-solid ratio, 16.86 min extraction time and 40.51% (v/v) ethanol, and the desirability was 0.681. The UPLC-ESI-MS analysis results revealed eleven kinds of phenolic compounds, including four major rare anthocyanins, among the antioxidants. All these results suggest that UAE is efficient at extracting antioxidants and has the potential to be used in industry for this purpose. PMID:24979404

Lai, Jixiang; Wang, Huifang; Wang, Donghui; Fang, Fang; Wang, Fengzhong; Wu, Tao

2014-01-01

78

Antiviral activities of flavonoids isolated from the bark of Rhus verniciflua stokes against fish pathogenic viruses In Vitro.  

PubMed

An 80% methanolic extract of Rhus verniciflua Stokes bark showed significant anti-viral activity against fish pathogenic infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia virus (VHSV) in a cell-based assay measuring virus-induced cytopathic effect (CPE). Activity-guided fractionation and isolation for the 80% methanolic extract of R. verniciflua yielded the most active ethyl acetate fraction, and methyl gallate (1) and four flavonoids: fustin (2), fisetin (3), butin (4) and sulfuretin (5). Among them, fisetin (3) exhibited high antiviral activities against both IHNV and VHSV showing EC(50) values of 27.1 and 33.3 ?M with selective indices (SI = CC(50)/EC(50)) more than 15, respectively. Fustin (2) and sulfuretin (5) displayed significant antiviral activities showing EC50 values of 91.2-197.3 ?M against IHNV and VHSV. In addition, the antiviral activity of fisetin against IHNV and VHSV occurred up to 5 hr post-infection and was not associated with direct virucidal effects in a timed addition study using a plaque reduction assay. These results suggested that the bark of R. verniciflua and isolated flavonoids have significant anti-viral activity against IHNV and VHSV, and also have potential to be used as anti-viral therapeutics against fish viral diseases. PMID:22538659

Kang, So Young; Kang, Ji-Young; Oh, Myung-Joo

2012-04-01

79

Detoxified extract of Rhus verniciflua stokes inhibits rotenone-induced apoptosis in human dopaminergic cells, SH-SY5Y.  

PubMed

Rhus verniciflua Stokes (RVS), traditionally used as a food supplement and in traditional herbal medicine for centuries in Korea, is known to possess various pharmacological properties. Environmental neurotoxins such as rotenone, a specific inhibitor of complex I provide models of Parkinson's disease (PD) both in vivo and in vitro. In this study, we investigated the neuroprotective effect of RVS against rotenone-induced toxicity in human dopaminergic cells, SH-SY5Y. Cells exposed to rotenone for 24 h-induced cellular injury and apoptotic cell death. Pretreatment of cells with RVS provided significant protection to SH-SY5Y cells. Further, RVS offered remarkable protection against rotenone-induced oxidative stress and markedly inhibited mitochondrial membrane potential (MMP) disruption. RVS also attenuated the up-regulation of Bax, Caspase-9 and Caspase-3 and down-regulation of Bcl-2. Moreover, pretreatment with RVS prevented the decrease in tyrosine hydroxylase (TH) levels in SH-SY5Y cells. Interestingly, RVS conferred profound protection to human dopaminergic cells by preventing the downregulation of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). These results suggest that RVS may protect dopaminergic neurons against rotenone-induced apoptosis by multiple functions and contribute to neuroprotection in neurodegenerative diseases, such as PD. PMID:21061154

Sapkota, Kumar; Kim, Seung; Park, Se-Eun; Kim, Sung-Jun

2011-03-01

80

Rhus verniciflua Extract Modulates Survival of MCF-7 Breast Cancer Cells through the Modulation of AMPK-Pathway.  

PubMed

Rhus verniciflua STOKES (RVS) is used as an anti-cancer agent in traditional herbal medicine. However, the underlying molecular mechanism of its action is poorly understood. Here, we elucidated the mechanism of the anti-cancer mechanism of RVS in MCF-7 human breast cancer cells. We found that RVS increased the phosphorylation of AMP-activated protein kinase (AMPK) and downstream acetyl-CoA carboxylase (ACC) and suppressed cell viability in an AMPK-dependent fashion. RVS also induced an increase in reactive oxygen species (ROS) levels. RVS-induced AMPK phosphorylation was not observed in the presence of N-acetyl-cysteine (NAC), which indicated that ROS is associated with RVS-induced AMPK phosphorylation. In addition, fluorescent staining (Annexin V/propidium iodide) revealed that RVS increased the expression of Annexin V, which indicates that RVS leads to cancer-induced apoptosis. Moreover, RVS increased the phosphorylation of p53 and the expression of Bax. The inhibition of AMPK blocked RVS-induced p53 phosphorylation and Bax expression, which suggests that AMPK is involved in RVS-induced cancer apoptosis. Taken together, these results demonstrate that RVS has anti-tumor effects on MCF-7 cells through an AMPK-signaling pathway. PMID:24553147

Lee, Jung Ok; Moon, Ji Wook; Lee, Soo Kyung; Kim, So Mi; Kim, Nami; Ko, Seong-Gyu; Kim, Hyeon Soo; Park, Sun Hwa

2014-05-01

81

Anti-inflammatory Activity of 1-docosanoyl Cafferate Isolated from Rhus verniciflua in LPS-stimulated BV2 Microglial Cells  

PubMed Central

Although various derivatives of caffeic acid have been reported to possess a wide variety of biological activities such as protection of neuronal cells against excitotoxicity, the biological activity of 1-docosanoyl cafferate (DC) has not been examined. The objective of the present study was to evaluate the anti-inflammatory effects of DC, isolated from the stem bark of Rhus verniciflua, on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Pretreatment of cells with DC significantly attenuated LPS-induced NO production, and mRNA and protein expression of iNOS in a concentration-dependent manner. DC also significantly suppressed LPS-induced release of cytokines such as TNF-? and IL-1? . Consistent with the decrease in cytokine release, DC dose-dependently and significantly attenuated LPS-induced mRNA expression of these cytokines. Furthermore, DC significantly suppressed LPS-induced degradation of IKB, which retains NF-kB in the cytoplasm. Therefore, nuclear translocation of NF-kB induced by LPS stimulation was significantly suppressed with DC pretreatment. Taken together, the present study suggests that DC exerts its anti-inflammatory activity through the suppression of NF-kB translocation to the nucleus.

Lee, Jae-Won; Cheong, Il-Young; Kim, Hae-Sung; Lee, Jae Jun; Lee, Yong-Suk; Kwon, Yong-Soo; Kim, Myong-Jo; Lee, Hee Jae; Kim, Sung-Soo

2011-01-01

82

Simultaneous determination of bioactive phenolic compounds in the stem extract of Rhus verniciflua stokes by high performance liquid chromatography.  

PubMed

A simple, sensitive, and precise reversed-phase liquid chromatographic method was developed for the quantitative determination of 4 bioactive phenolic compounds (gallic acid, fustin, fisetin, and sulfuretin) from the stem extract of Rhus verniciflua stokes. Chromatographic analysis was performed on a Capcell Pak C18 column (150 × 4.6 mm, 3 ?m) with a mobile phase consisting of 0.1% formic acid and 90% acetonitrile at a flow rate of 1 mL/min. Quantitation was performed using a UV-vis detector at 260 nm. The method was validated in terms of selectivity, linearity, accuracy, precision, and recovery. Excellent linear behavior was observed over the investigated concentration range (10-500 ?g/mL for gallic acid, fustin, and fisetin; 0.5-100 ?g/mL for sulfuretin) with correlation coefficient (r(2)) values >0.99. The intra- and inter-day precision over the concentration range of compounds was less than 6.65% (relative standard deviation) and the accuracy was between 92.42% and 103.62%. The mean recoveries for all the analytes were more than 92.18%. This method was successfully applied for the analysis of bioactive phenolic compounds in the R. verniciflua extracts. PMID:23993553

Kim, Sun-A; Kim, Seung Hyun; Kim, In Sook; Lee, Dongho; Dong, Mi-Sook; Na, Chun-Soo; Nhiem, Nguyen Xuan; Yoo, Hye Hyun

2013-12-15

83

Cognitive-enhancing effects of Rhus verniciflua bark extract and its active flavonoids with neuroprotective and anti-inflammatory activities.  

PubMed

The neuroprotective potential of flavonoids within the brain comprises anti-apoptosis of neuronal cells, anti-neuroinflammation and enhancement of cognitive function. We reported that Rhus vernciflua inhibits glutamate-induced neurotoxicity in primary cultured rat cortical cells. Here we narrowed it down to get neuroprotective fractions from the plant yielding flavonoid-rich ethyl acetate fraction (PREF). Among its active flavonoids, fisetin exhibited not only inhibitory effect against lipopolysaccharide (LPS)-induced neuroinflammation by suppressing inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 but also memory enhancing effects via reactivation of cAMP responsive element binding protein (CREB)-brain derived neurotrophic factor (BDNF) pathway in memory-impaired mice by scopolamine. Butein also showed a similar activity to fisetin even though to a lesser extent. The neuroprotection by PREF and selected flavonoids may involve maintenance of antioxidant defense mechanism including glutathione peroxidase (GSH-Px), glutathione reductase (GR) and superoxide dismutase (SOD). Conclusively, we demonstrate the R. vernciflua bark extract and its active flavonoids with potent neuroprotective and anti-inflammatory effects might be good therapeutic candidates as cognitive-enhancers. PMID:23688860

Cho, Namki; Lee, Ki Yong; Huh, Jungmoo; Choi, Ji Hoon; Yang, Heejung; Jeong, Eun Ju; Kim, Hong Pyo; Sung, Sang Hyun

2013-08-01

84

Polyphenols from the bark of Rhus verniciflua and their biological evaluation on antitumor and anti-inflammatory activities.  

PubMed

Bioassay-guided fractionation and chemical investigation of the extract of Rhus verniciflua bark resulted in the identification of six polyphenols, rhusopolyphenols A-F (1-6), together with four known compounds including (2R,3S,10S)-7,8,9,13-tetrahydroxy-2-(3,4-dihydroxyphenyl)-2,3-trans-3,4-cis-2,3,10-trihydrobenzopyrano[3,4-c]-2-benzopyran-1-one (7), peapolyphenol C (8), cilicione-b (9) and (?R)-?,3,4,2',4'-pentahydroxydihydrochalcone (10). The structures of these polyphenols were elucidated by spectroscopic analysis, including 1D and 2D NMR, and HR-ESIMS, and their absolute configurations were further confirmed by a combination of chemical methods and CD data analysis. All isolates were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and compounds 4-6, 9 and 10 showed antiproliferative activity against the tested cells, with IC50 values of 3.31-18.51 ?M. On the basis of the expanded understanding that inflammation is a crucial cause of tumor progression, the anti-inflammatory activities of these compounds were determined by measuring nitric oxide (NO) levels in the medium of murine microglia BV-2 cells. Compounds 5 and 10 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells with IC50 values of 28.90 and 12.70 ?M, respectively. PMID:23752101

Kim, Ki Hyun; Moon, Eunjung; Choi, Sang Un; Kim, Sun Yeou; Lee, Kang Ro

2013-08-01

85

Chemoprevention of a flavonoid fraction from Rhus verniciflua Stokes on aflatoxin B1-induced hepatic damage in mice.  

PubMed

Since aflatoxin B(1) (AFB(1))-mediated hepatic damage is related to the production of AFB(1)-8,9-epoxide and reactive oxygen species, bioactive compounds having antioxidant potentials are suggested to be capable of reducing AFB(1)-induced toxicity. We previously purified a mixture of flavonoids that we named RCMF (Rhus verniciflua Stokes chloroform-methanol fraction), from a traditional Korean food additive and herbal medicine. RCMF exhibited various biological effects, including antioxidant and antitumor activities. In this study, we examined whether RCMF protects against AFB(1)-induced liver injury using in vitro and in vivo systems. Pretreatment of HepG2 cells with RCMF significantly reduced AFB(1)-stimulated production of ROS and malondialdehyde (MDA) to the control levels. RCMF also prevented the reduction in HepG2 cell viability caused by AFB(1). Oral administration of RCMF to mice significantly suppressed an AFB(1)-induced increase in serum levels of alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase. It also prevented MDA formation and blocked decreases in glutathione levels and superoxide dismutase activities in the livers of AFB(1)-treated mice. In addition, RCMF supplementation prevented an AFB(1) -induced decrease in serum titers of IgA and IgG1. Collectively, these results suggest that RCMF attenuates AFB(1)-mediated damage to the liver, and that this effect is at least partially related to the restoration of antioxidant defense systems and an increase in AFB(1)-GSH conjugate formation. PMID:20737424

Choi, Ki-Choon; Chung, Wan-Tae; Kwon, Jung-Kee; Jang, Yong-Suk; Yu, Ji-Yeon; Park, Seung-Moon; Lee, Jeong-Chae

2011-03-01

86

Tree Squirrels  

Microsoft Academic Search

In this chapter tree squirrels are divided into three groups: large tree squirrels, pine squirrels, and flying squirrels. Large tree squirrels include fox (Sciurus niger), eastern gray (Sciurus carolinensis), western gray (Sciurus griseus), and tassel-eared (Sciurus aberti) squirrels. Fox squirrels (Fig. 1) measure 18 to 27 inches (46 to 69 cm) from nose to tip of tail. They weigh about

Jeffrey J. Jackson

1994-01-01

87

Randomized controlled trial of a water-soluble nail lacquer based on hydroxypropyl-chitosan (HPCH), in the management of nail psoriasis  

PubMed Central

Background Nail psoriasis occurs in up to 50% of patients affected by psoriasis, with a significant impact on quality of life that leads to a real clinical need for new therapeutic options. Aim To confirm whether the strengthening and hardening properties of the hydroxypropyl-chitosan (HPCH) nail lacquer could improve the structure of the nail plates on psoriatic nails. Materials and methods A randomized, double-blind, placebo controlled, parallel-group trial was carried out to evaluate the efficacy and tolerability of a hydrosoluble nail lacquer containing HPCH, Equisetum arvense, and methylsulfonylmethane on nail psoriasis. The test product or a placebo was applied once daily for 24 weeks to all fingernails. Efficacy assessments were performed on the target fingernail by means of the modified Nail Psoriasis Severity Index score. A cut-off score of 4 was considered to define the clinical cure rate (ie, Cure ?4, Failure >4). Results After 24 weeks, the clinical cure rate showed the statistically significant superiority of the HPCH nail lacquer compared to placebo in both the intention-to-treat (Fisher’s exact test, P=0.0445) and the per protocol population (Fisher’s exact test, P=0.0437). This superiority was already present after 16 weeks of treatment. Moreover, the analysis of the modified Nail Psoriasis Severity Index-50 showed a statistically significant clinical improvement after 12 weeks of treatment in comparison to the results obtained after 8 weeks (Fisher’s exact test, P<0.05). Conclusion The trial showed that HPCH nail lacquer could be a new, valid, effective, and safe option for decreasing the signs of nail dystrophy in psoriatic patients.

Cantoresi, Franca; Caserini, Maurizio; Bidoli, Antonella; Maggio, Francesca; Marino, Raffaella; Carnevale, Claudia; Sorgi, Paola; Palmieri, Renata

2014-01-01

88

Anaerobic reactions of Rhus vernicifera laccase and its type-2 copper-depleted derivatives with hexacyanoferrate(II).  

PubMed

Anaerobic reactions of Rhus vernicifera laccase and its type-2 copper-depleted derivatives with hexacyanoferrate(II) were investigated by absorption and e.s.r. spectroscopy. When native laccase was treated with excess hexacyanoferrate(II), the type-1 and type-2 coppers were immediately reduced and the e.s.r. signal due to type-3 copper was transiently observed. After incubation, a novel e.s.r. signal (g parallel = 2.31, g perpendicular = 2.08) developed together with the type-1 copper signal. Only the novel e.s.r. signal was left after the sample had been treated with ascorbate. In the corresponding absorption spectrum, a new band was observed at around 490 nm. A similar new e.s.r. signal did not appear for the type-2-copper-depleted (T2D) laccase, in which the type-3 copper had been reduced during the procedure to deplete the type-2 copper. On the other hand, the novel e.s.r. signal emerged when the type-3 copper in T2D laccase had been previously reoxidized with H2O2. The novel e.s.r. signal was not significantly saturated even by 200 mV microwave power at 4 K. Quantitative estimations and a small molecule study for CuII-FeII(CN)6 and CuII-FeIII(CN)6 systems suggested that the novel e.s.r. signal corresponds to some sort of adduct involving the type-3 copper and hexacyanoferrate(II). PMID:1320374

Sakurai, T

1992-06-15

89

Inhibition of Human Cytochrome P450 Enzymes by Allergen Removed Rhus verniciflua Stoke Standardized Extract and Constituents  

PubMed Central

Objective. Potential interactions between herbal extracts and the cytochrome P450 (CYP) system lead to serious adverse events or decreased drug efficacy. Rhus verniciflua stoke (RVS) and its constituents have been reported to have various pharmacological properties. We evaluated the inhibitory potential of RVS and its constituents on the major CYP isoforms. Methods. The effects of allergen removed RVS (aRVS) standardized extract and major components, fustin and fisetin isolated from aRVS, were evaluated on CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 isoenzyme activity by a luminescent CYP recombinant human enzyme assay. Results. The aRVS extract showed relative potent inhibitory effects on the CYP2C9 (IC50, <0.001??g/mL), CYP2C19 (IC50, 9.68??g/mL), and CYP1A2 (IC50, 10.0??g/mL). However, it showed weak inhibition on CYP3A4 and CYP2D6. Fustin showed moderate inhibitory effects on the CYP2C19 (IC50, 64.3??g/mL) and weak inhibition of the other CYP isoforms similar to aRVS. Fisetin showed potent inhibitory effects on CYP2C9, CYP2C19, and CYP1A2. Fisetin showed moderate inhibition of CYP2D6 and weak inhibition of CYP3A4. Conclusions. These results indicate that aRVS, a clinically available herbal medicine, could contribute to herb-drug interactions when orally coadministered with drugs metabolized by CYP2C9, CYP2C19, and CYP1A2.

Jung, Hyunsik; Lee, Sanghun

2014-01-01

90

Anaerobic reactions of Rhus vernicifera laccase and its type-2 copper-depleted derivatives with hexacyanoferrate(II).  

PubMed Central

Anaerobic reactions of Rhus vernicifera laccase and its type-2 copper-depleted derivatives with hexacyanoferrate(II) were investigated by absorption and e.s.r. spectroscopy. When native laccase was treated with excess hexacyanoferrate(II), the type-1 and type-2 coppers were immediately reduced and the e.s.r. signal due to type-3 copper was transiently observed. After incubation, a novel e.s.r. signal (g parallel = 2.31, g perpendicular = 2.08) developed together with the type-1 copper signal. Only the novel e.s.r. signal was left after the sample had been treated with ascorbate. In the corresponding absorption spectrum, a new band was observed at around 490 nm. A similar new e.s.r. signal did not appear for the type-2-copper-depleted (T2D) laccase, in which the type-3 copper had been reduced during the procedure to deplete the type-2 copper. On the other hand, the novel e.s.r. signal emerged when the type-3 copper in T2D laccase had been previously reoxidized with H2O2. The novel e.s.r. signal was not significantly saturated even by 200 mV microwave power at 4 K. Quantitative estimations and a small molecule study for CuII-FeII(CN)6 and CuII-FeIII(CN)6 systems suggested that the novel e.s.r. signal corresponds to some sort of adduct involving the type-3 copper and hexacyanoferrate(II).

Sakurai, T

1992-01-01

91

Single and 90-day repeated oral dose toxicity studies of fermented Rhus verniciflua stem bark extract in Sprague-Dawley rats.  

PubMed

Fermented Rhus verniciflua stem bark (FRVSB) extract, an urushiol-free extract of Rhus verniciflua Stokes (RVS) fermented with Fomitella fraxinea, has various biological activities. The present study was carried out to investigate the potential toxicity of the FRVSB extract following single and repeated oral administration to Sprague-Dawley rats. In the single dose toxicity study, the FRVSB extract was administered orally to male and female rats at single doses of 0, 2500, 5000, and 10,000mg/kg. No animals died and no toxic changes were observed in clinical signs, body weight, and necropsy findings during the 15-day period following administration. In the repeated dose toxicity study, the FRVSB extract was administered orally to male and female rats for 90days at doses of 0, 556, 1667, and 5000mg/kg/day. There were no treatment-related adverse effects in clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology at any dose tested. The approximate lethal dose of the FRVSB extract was >10,000mg/kg in both genders, the oral no-observed-adverse-effect level of the FRVSB extract was >5000mg/kg/day in both genders, and no target organs were identified. PMID:23416650

Shin, Seo-Ho; Koo, Kyo-Hwan; Bae, Jin-Sook; Cha, Seung-Bum; Kang, In-Soo; Kang, Min-Soo; Kim, Hak-Soo; Heo, Hyun-Suk; Park, Min-Su; Gil, Gi-Hyun; Lee, Joo-Young; Kim, Kap-Ho; Li, Yinghua; Lee, Hyun-Kul; Song, Si-Whan; Choi, Han-Seok; Kang, Boo-Hyon; Kim, Jong-Choon

2013-05-01

92

Keratinocyte intercellular adhesion molecule-1 (ICAM-1) expression precedes dermal T lymphocytic infiltration in allergic contact dermatitis (Rhus dermatitis).  

PubMed

The ability of small molecules such as urushiol, present as a wax on the poison ivy leaf surface, to cause allergic contact dermatitis (rhus dermatitis) has fascinated immunologists for decades. Current dogma suggests that these epicutaneously applied catechol-containing molecules serve as haptens to conjugate with larger proteins via reactive o-quinone intermediates. These complexes are then recognized as foreign antigens by the immune system and elicit a hypersensitivity reaction. Phorbol ester can directly induce cultured keratinocyte (KC) intercellular adhesion molecule-1 (ICAM-1) expression via a protein kinase C (PK-C)-dependent mechanism. As urushiol is also a known PK-C agonist, we asked if topical application of a poison ivy/oak mixture could directly induce epidermal KC ICAM-1 expression. During the pre-erythematous phase of this reaction (4 to 20 hours), epidermal KCs expressed ICAM-1; this "initiation phase" preceded the appearance of activated memory T lymphocytes in the papillary dermis, and thus appeared to be nonlymphokine mediated. A near-contiguous cellular-adhesion molecular network was identified by ICAM-1 staining of basal KCs, dermal dendrocytes, and endothelial cells. During the second 24-hour period with the onset of erythema and edema, there was an "amplification phase" of more intense KC ICAM-1 expression coupled with relatively weak KC HLA-DR expression that coincided with dermal and epidermal T-cell infiltration. This suggests the presence of lymphokines, such as gamma interferon, during the amplification phase because of KC HLA-DR expression. On cultured KCs, urushiol directly induced ICAM-1 expression but not HLA-DR. Thus, in addition to functioning as an antigenic hapten, urushiol directly induces KC ICAM-1 expression. The KC ICAM-1 expression may then alter the dynamic trafficking of memory T cells in the epidermis, so as to initiate cutaneous inflammation in a nonantigen specific manner. This initiation phase is followed by T-cell infiltration and consequent lymphokine production that significantly amplifies the original stimulus. Thus much can still be learned about the molecular pathophysiology of this common type of cutaneous inflammation. PMID:2574536

Griffiths, C E; Nickoloff, B J

1989-12-01

93

Keratinocyte intercellular adhesion molecule-1 (ICAM-1) expression precedes dermal T lymphocytic infiltration in allergic contact dermatitis (Rhus dermatitis).  

PubMed Central

The ability of small molecules such as urushiol, present as a wax on the poison ivy leaf surface, to cause allergic contact dermatitis (rhus dermatitis) has fascinated immunologists for decades. Current dogma suggests that these epicutaneously applied catechol-containing molecules serve as haptens to conjugate with larger proteins via reactive o-quinone intermediates. These complexes are then recognized as foreign antigens by the immune system and elicit a hypersensitivity reaction. Phorbol ester can directly induce cultured keratinocyte (KC) intercellular adhesion molecule-1 (ICAM-1) expression via a protein kinase C (PK-C)-dependent mechanism. As urushiol is also a known PK-C agonist, we asked if topical application of a poison ivy/oak mixture could directly induce epidermal KC ICAM-1 expression. During the pre-erythematous phase of this reaction (4 to 20 hours), epidermal KCs expressed ICAM-1; this "initiation phase" preceded the appearance of activated memory T lymphocytes in the papillary dermis, and thus appeared to be nonlymphokine mediated. A near-contiguous cellular-adhesion molecular network was identified by ICAM-1 staining of basal KCs, dermal dendrocytes, and endothelial cells. During the second 24-hour period with the onset of erythema and edema, there was an "amplification phase" of more intense KC ICAM-1 expression coupled with relatively weak KC HLA-DR expression that coincided with dermal and epidermal T-cell infiltration. This suggests the presence of lymphokines, such as gamma interferon, during the amplification phase because of KC HLA-DR expression. On cultured KCs, urushiol directly induced ICAM-1 expression but not HLA-DR. Thus, in addition to functioning as an antigenic hapten, urushiol directly induces KC ICAM-1 expression. The KC ICAM-1 expression may then alter the dynamic trafficking of memory T cells in the epidermis, so as to initiate cutaneous inflammation in a nonantigen specific manner. This initiation phase is followed by T-cell infiltration and consequent lymphokine production that significantly amplifies the original stimulus. Thus much can still be learned about the molecular pathophysiology of this common type of cutaneous inflammation. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Griffiths, C. E.; Nickoloff, B. J.

1989-01-01

94

Role of Structural Changes Induced in Biological Membranes by Hydrolysable Tannins from Sumac Leaves (Rhus typhina L.) in their Antihemolytic and Antibacterial Effects.  

PubMed

In this study, we found that the sumac tannins (Rhus typhina L.) exert to a various extent antihemolytic effects and antibacterial activity against Bacillus cereus and Pseudomonas aeruginosa depending on structural specificity of bacteria and different mechanisms of their toxic action. The sumac tannins exert the most expressed activity against B. cereus. The antihemolytic effect of the sumac tannins seems to be connected to a greater extent with their modifying action on the erythrocyte membrane structure. It was found that the sumac tannins are incorporated into the erythrocyte membrane, causing transformation of discocytes into echinocytes and enhancing the rigidity of the hydrophilic region of the lipid bilayer. We suggest that the embedding of sumac tannins into the membrane of erythrocytes alters their physical properties and, as a consequence, can limit their interaction with bacterial toxins. PMID:24793101

Olchowik-Grabarek, Ewa; Swiecicka, Izabela; Andreeva-Kovaleskaya, Zhanna; Solonin, Alexander; Bonarska-Kujawa, Dorota; Kleszczy?ska, Halina; Mavlyanov, Saidmukhtar; Zamaraeva, Maria

2014-06-01

95

Tree frog  

NSDL National Science Digital Library

This tree frog can be found living in jungles and forests. Two reasons why the common frog is considered to be an amphibian are because it lays eggs in water and its spawn goes through metamorphosis to reach adulthood.

Hans Hillewaert (None;)

2008-04-20

96

Molecular Structure of Urushiol  

NSDL National Science Digital Library

Urushiol is a yellow oil comprised of a mixture of organic compounds containing a catechol (1,2-hydroxy benzene) and a pentadecyl or heptadecyl side chain; some side chains may be unsaturated. The earliest use of urushiol was in the art of ancient Asia, where works of art were coated in lacquer finishes derived from the trees Toxicodendron vernicifluum or Rhus verniciflua. In fact, the name urushiol is derived from urushi, the Japanese word for the lacquer prepared from the sap of the Japanese lacquer tree ("kiurushi"). During the lacquering process, the phenols oxidize and polymerize with the help of enzymes to yield a coating that is hard and resistant to mechanical stress. Inhabitants of North America are familiar with the more malevolent side of urushiol-as the active ingredient of poison ivy and poison oak. Most people are highly allergic to urushiol and will develop redness, painful itching, and blistering of the skin if they touch even minute amounts of the oil. Interestingly, one of the most effective remedies for poison ivy comes also from a plant. The Jewelweed plant (Impatiens capensis) found in North American hardwood forests produces a chemical called Lawsone (a naphthoquinone) with antihistamine and anti-inflammatory properties that lessen the effects of urushiol on the skin.

2006-04-19

97

Christmas Tree  

NSDL National Science Digital Library

Last year, the front page of the Christmas Day New York Times talked about how you could do `finger xmastree@cygnus.com' to find out the current state of the Christmas tree in the offices of Cygnus Support. Well, it's back again this year. But, we wouldn't want you to be bored! "Oh, ho hum, that same boring thing all over again...been there, saw that." So to follow the example of a few million enthusiasts, the increasingly-popular World Wide Web is now toting its very own Christmas tree, which is so interactive it's almost like it's in your home. (Well, not quite. But if you'd like to send some wrapped gifts, I'm sure we wouldn't be upset.) Along with getting to look at a small photo of the tree when you first connect to it, you may: choose to see a full-size version of that picture -- they are updated every two minutes; choose to watch an MPEG movie of the tree which is 20 frames long, so you can watch the lights blink, etc. This is updated every fifteen minutes; vote on the different features of the tree, and every fifteen minutes the system will do the vote count and change the tree accordingly; send any one of ten random cards to a given email address; find out the technical details of how it was done, if you're really that interested. If you have any comments, suggestions, or complaints (come to think of it, you can keep the complaints), write to

98

Trees, Soil and Water  

NSDL National Science Digital Library

Trees, soil and water: Journey to Forever - health care for mountains, trees for deserts, trees for people, forest, forestry, deforestation, erosion, soil conservation, water conservation, desertification.

Addison, Keith

2010-01-01

99

Greenhouse trees  

SciTech Connect

Michigan State University has been conducting research on growth control of woody plants with emphasis on commercial plantations. The objective was to develop the optimum levels for the major factors that affect tree seedling growth and development so that high quality plants can be produced for a specific use. This article describes the accelerated-optimal-growth (AOG) concept, describes precautions to take in its application, and shows ways to maximize the potential of AOG for producing ornamental trees. Factors considered were container growing system; protective culture including light, temperature, mineral nutrients, water, carbon dioxide, growth regulators, mycorrhizae, growing media, competition, and pests; size of seedlings; and acclamation. 1 table. (DP)

Hanover, J.W.; Hart, J.W.

1980-05-09

100

Reading trees.  

PubMed

Are birds dinosaurs? Answers to this question yield various responses, depending on a particular viewpoint. From the perspective of a common understanding of recent theories of the origin of birds and their potential precursor (ancestral) animals, then, yes, birds are a kind of dinosaur, having evolved from one or another non-avian dinosaur (Bostwick 2003). From the perspective of public understanding of science (how to inform the general public of biology's latest findings), then, yes, birds are dinosaurs, at least they are a kind of dinosaur, one that young children can actually hold in their hands (e.g., Maugh 2012). These two perspectives, largely derived from phylogenetic reasoning, contrast with the perspective from classification, which asks different questions: What are birds; what are dinosaurs; and how are they related to one another? Addressing these questions raises the issue of trees in classification (phylogenetic or otherwise) and how to read them. This is not as easy a task as is often suggested in the recent literature on tree-reading and tree-thinking (first noted long ago by O'Hara 1988, see Baum and Smith 2012 for a first book-length treatment).                      The role of tree-thinking in classification is applied after a tree has been constructed and natural groups established. For instance, it would seem premature to infer phylogenies on poorly classified taxa, such as invertebrates, reptiles and so on, as these groupings are artificial. Doing so would only result in erroneous hypotheses that cannot be substantiated. The role of classification, however, is to make sure that the natural groups are justified, and in order to do this it is vital that those groups are understood. Birds represent a monophyletic group, which has series of unique characteristics that it shares with other theropods (i.e., bipedal saurischian dinosaurs). Dinosaurs, as usually conceived, are a group of non-monophyletic organisms that variously share closer characteristics (i.e., relationships) with other taxa rather than uniquely among themselves. In the case of dinosaurs (as Dinosauria) and classification, what is at stake is a taxonomic name, rather than a unique group of character traits. Below we outline and compare two contrasting ways of reading trees, one way, concerned with classification, yielding the view that, no, birds are not dinosaurs. PMID:24943430

Ebach, Malte C; Williams, David M

2014-01-01

101

Protective effect of detoxified Rhus verniciflua stokes on human keratinocytes and dermal fibroblasts against oxidative stress and identification of the bioactive phenolics.  

PubMed

Oxidative stress due to the over-production of reactive oxygen species (ROS) is associated with human skin aging. This study was designed to identify the bioactive phenolics in detoxified Rhus verniciflua Stokes (DRVS) that may protect human skin against oxidative stress. Under oxidative stress caused by H?O?, the 40% (v/v) aqueous methanol extract of DRVS protected human keratinocytes in a dose-dependent manner. The expression of matrix metalloproteinase-1 (MMP-1) was also inhibited by the DRVS extract in human dermal fibroblasts-neonatal cells exposed to ultraviolet A. The major bioactive phenolics of DRVS were tentatively identified by LC/Q-TOF-ESI-MS/MS, and included gallic acid, 2-(ethoxymethoxy)-3-hydroxyphenol, fustin, a fustin isomer, tetragalloyl glucose, pentagalloyl glucose, fisetin, sulfuretin, a sulfuretin isomer, and butein. The results suggest that a DRVS extract may be effective in slowing skin aging through its antioxidative properties and by down-regulating MMP-1 expression. Further studies are needed to examine whether this effect would be mediated by the phenolics identified in this study. PMID:23924730

Liu, Chun-Shan; Nam, Tae-Gyu; Han, Min-Woo; Ahn, Soo-mi; Choi, Han Seok; Kim, Tae Young; Chun, Ock K; Koo, Sung I; Kim, Dae-Ok

2013-01-01

102

Impact of Standardized Allergen-Removed Rhus verniciflua Stokes Extract on Advanced Adenocarcinoma of the Ampulla of Vater: A Case Series  

PubMed Central

Background. Adenocarcinoma of the ampulla of Vater (AAV) is a rare malignancy that has a better prognosis than other periampullary cancers. However, the standard treatment for patients with relapsed or metastatic AAV has not been established. We investigated the clinical feasibility of standardized allergen-removed Rhus verniciflua stokes (aRVS) extract for advanced or metastatic AAV. Patients and Methods. From July 2006 to April 2011, we retrospectively reviewed all patients with advanced AAV treated with aRVS extract alone. After applying inclusion/exclusion criteria, 12 patients were eligible for the final analysis. We assessed the progression-free survival (PFS) and overall survival (OS) of these patients during the follow-up period. Results. The median aRVS administration period was 147.0 days (range: 72–601 days). The best tumor responses according to Response Evaluation Criteria in Solid Tumors were as follows: two with complete response, two with stable disease, and eight with progressive disease. The median OS was 15.1 months (range: 4.9–25.1 months), and the median PFS was 3.0 months (range: 1.6–11.4 months). Adverse reactions to the aRVS treatment were mostly mild and self-limiting. Conclusions. Prolonged survival was observed in patients with advanced AAV under the treatment of standardized aRVS extract without significant adverse effects.

Choi, Woncheol; An, Soomin; Kwon, Eunmi; Eo, Wankyu; Lee, Sanghun

2013-01-01

103

Hypolipidemic and antioxidative effects of the plant glycoprotein (36 kDa) from Rhus verniciflua stokes fruit in Triton WR-1339-induced hyperlipidemic mice.  

PubMed

We investigated the hypolipidemic and antioxidative effects on male ICR mice of a glycoprotein isolated from Rhus verniciflua Stokes (RVS) fruit. The administration of the RVS glycoprotein (100 mg/kg) for two weeks resulted in a significant decrease in such plasma lipid levels as total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL). The levels of TC, TG and LDL in the hyperlipidemic model were significantly increased, whereas the high-density lipoprotein (HDL) level was considerably decreased. The 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity and the level of thiobarbituric acid-reactive substances (TBARS) were significantly elevated, whereas the production of nitric oxide (NO) was diminished. Moreover, the administration of the RVS glycoprotein prior to inducing hyperlipidemic mice suppressed the increase in the plasma lipid levels (TC, TG and LDL), and decrease in the HDL level in Triton WR-1339-induced hyperlipidemic mice. Furthermore, the RVS glycoprotein significantly inhibited the activity of HMG-CoA reductase and the levels of TBARS in the hyperlipidemic mice. In addition, the activities of detoxicant enzymes [catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx)] were gradually augmented after a supplement with the RVS glycoprotein. The results suggest that the RVS glycoprotein would be effective in preventing an increase in the plasma lipid levels and in improving the antioxidant levels. This protein might be useful as a therapeutic agent. PMID:16495662

Oh, Phil-Sun; Lee, Sei-Jung; Lim, Kye-Taek

2006-02-01

104

Neuroprotective and anti-inflammatory effects of flavonoids isolated from Rhus verniciflua in neuronal HT22 and microglial BV2 cell lines.  

PubMed

The neuroprotective and anti-inflammatory activities of the methanolic extract of Rhus verniciflua Stokes (Anacardiaceae) were investigated with mouse hippocampal and microglial cells. Bioactivity-guided isolation yielded 10 flavonoids including fustin (1), fisetin (2), sulfuretin (3), butein (4), butin (5), eriodictyol (6), morin hydrate (7), quercetin (8), kaempferol (9) and isoliquiritigenin (10). Among the isolated flavonoids, compounds 2-5 significantly protected the murine hippocampal HT22 cells against glutamate-induced neurotoxicity and attenuated reactive oxygen species (ROS) generations. In addition, these flavonoids significantly maintained antioxidative defense systems preserving the activities of superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GSH-Px) and the content of glutathione (GSH) decreased by glutamate insult. These compounds also showed significant inhibitory effects on LPS-induced nitric oxide (NO) production in BV2 cells. Especially, compound 4 dose-dependently suppressed the expression of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These results suggest that these flavonoids possess therapeutic potentials as a multipotent agent against neurodegenerative diseases related to oxidative stress and pathological inflammatory responses. PMID:22465834

Cho, Namki; Choi, Ji Hoon; Yang, Heejung; Jeong, Eun Ju; Lee, Ki Yong; Kim, Young Choong; Sung, Sang Hyun

2012-06-01

105

Juvenile Rhus glabra leaves have higher temperatures and lower gas exchange rates than mature leaves when compared in the field during periods of high irradiance.  

PubMed

We sought to test the hypothesis that stomatal development determines the timing of gas exchange competency, which then influences leaf temperature through transpirationally driven leaf cooling. To test this idea, daily patterns of gas exchange and leaflet temperature were obtained from leaves of two distinctively different developmental stages of smooth sumac (Rhus glabra) grown in its native habitat. Juvenile and mature leaves were also sampled for ultrastructural studies of stomatal development. When plants were sampled in May-June, the hypothesis was supported: juvenile leaflets were (for part of the day) from 1.4 to 6.0 degrees C warmer than mature leaflets and as much as 2.0 degrees C above ambient air temperature with lower stomatal conductance and photosynthetic rates than mature leaflets. When measurements were taken from July to October, no significant differences were observed, although mature leaflet gas exchange rates declined to the levels of the juvenile leaves. The gas exchange data were supported by the observations that juvenile leaves had approximately half the number of functional stomata on a leaf surface area basis as did mature leaves. It was concluded that leaf temperature and stage of leaf development in sumac are strongly linked with the higher surface temperatures observed in juvenile leaflets in the early spring possibly being involved in promoting photosynthesis and leaf expansion when air temperatures are cooler. PMID:18849091

Snider, John L; Choinski, John S; Wise, Robert R

2009-05-01

106

Rhus verniciflua Stokes prevents cisplatin-induced cytotoxicity and reactive oxygen species production in MDCK-I renal cells and intact mice.  

PubMed

Cisplatin-induced oxidative stress can cause liver and kidney damage, thus limiting therapeutic efficacy. Thus, in the present study, since Rhus verniciflua Stokes (RVS) containing flavonoids has antioxidant effects, we investigated whether it can protect cisplatin-induced toxicity in vitro and in vivo, The in vitro effects of RVS on the cell viability and reactive oxygen species (ROS) production were investigated using cisplatin-treated Madin-Darby Canine kidney (MDCK)-I renal cells. Its in vivo effects were also studied in BALB/c mice inoculated with CT-26 colon adenocarcinoma cells and treated with cisplatin with or without RVS. Liver and renal functions were assessed together with indices of tissue oxidation. RVS prevented cisplatin-induced cytotoxicity and ROS release against MDCK-I cells. RVS alone exerted modest antitumor activity against CT-26 cells. When used concurrently with cisplatin, RVS prevented the increases in serum blood urea nitrogen (BUN), creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and NO, while reducing liver and kidney tissue MDA content, and increasing catalase, glutathione (GSH), and superoxide dismutase (SOD) activities. Moreover, the antitumor efficacy of cisplatin was not altered by concurrent administration of RVS. These findings demonstrate that RVS prevents cisplatin-induced toxicity in vitro and in vivo via an antioxidant activity without hurting its antitumor effectiveness, suggesting that RVS can be usefully applied to the neoplastic patients as a combined chemopreventive agent with cisplatin. PMID:19150236

Lee, Joo-Ho; Lee, Hyo-Jung; Lee, Hyo-Jeong; Choi, Won-Cheol; Yoon, Seong-Woo; Ko, Seong-Gyu; Ahn, Kwang Seok; Choi, Seung-Hoon; Ahn, Kyoo-Seok; Lieske, John C; Kim, Sung-Hoon

2009-03-01

107

The Tree-to-Tree Correction Problem  

Microsoft Academic Search

The tree-to-tree correctmn problem Is to determine, for two labeled ordered trees T and T', the distance from T to T' as measured by the mlmmum cost sequence of edit operaUons needed to transform T into T' The edit operations investigated allow changing one node of a tree into another node, deleting one node from a tree, or inserting a

Kuo-Chung Tai

1979-01-01

108

Tree Troubles  

NSDL National Science Digital Library

This Topic in Depth explores some of the diseases and other threats that certain trees must contend with to remain healthy and vital. The first website (1), from the USDA Forest Service-St. Paul Field Office, contains a collection of archived publications designed to help people diagnose, control, and identify various threats to different types of trees. Examples of these publications include: How to Control Sapstreak Disease of Sugar Maple; How to Differentiate Dutch Elm Disease From Elm Phloem Necrosis; How to Identify and Manage Needlecast Diseases on Balsam Fir; and How to Manage Eastern White Pine to Minimize Damage from Blister Rust and White Pine Weevil, to name few. The second (2) site, Forest & Shade Tree Pathology, is an online textbook that was developed by Dr. James J. Worrall, a plant pathologist for the USDA Forest Service, and former professor at the College of Environmental Science and Forestry, State University of New York. Dr. Worrall's site contains information about rusts, foliage and root diseases, parasitic plants, cankers, abiotic diseases, and wilts as well as disease profiles for Swiss Needle Cast; Oak Wilt, Chestnut Blight, Armillaria Root Disease, and more. The third (3) site, Oak Wilt: A Threat to Red Oaks & White Oaks Species, was created by Dr. David L. Roberts at Michigan State University Extension. Dr. Robert's concise site contains brief sections addressing oak wilt distribution, field diagnosis, management, disease cycle, and more. The fourth (4) site, from the California Oak Mortality Task Force, contains images, publications, maps, and information about Sudden Oak Death-related research, management recommendations, nursery issues, and regulations. The final three websites come from the USDA Forest Service and contain information about different insect threats. The fifth (5) site offers information about the emerald ash borer. The sixth (6) site provides information about the gypsy moth, and the final (7) site contains information about the Asian longhorned beetle.

109

Trees in the Landscape.  

ERIC Educational Resources Information Center

Strategies for using trees in classroom instruction are provided. Includes: (1) activities (such as tree identification, mapping, measuring tree height/width); (2) list of asthetic, architectural, engineering, climate, and wildlife functions of trees; (3) tree discussion questions; and (4) references. (JN)

Webb, Richard; Forbatha, Ann

1982-01-01

110

Trees and Air Quality  

NSDL National Science Digital Library

In this activity, students describe the positive effects that trees have on air quality and determine how to landscape a home with trees to decrease energy use. Students will draw a map of their yard or school site showing the location of trees and check a leaf of each tree for particulates. They will then make observations on several different days to determine which trees save energy and draw on their map where more trees should be planted to save energy.

111

Estimating species trees from unrooted gene trees.  

PubMed

In this study, we develop a distance method for inferring unrooted species trees from a collection of unrooted gene trees. The species tree is estimated by the neighbor joining (NJ) tree built from a distance matrix in which the distance between two species is defined as the average number of internodes between two species across gene trees, that is, average gene-tree internode distance. The distance method is named NJ(st) to distinguish it from the original NJ method. Under the coalescent model, we show that if gene trees are known or estimated correctly, the NJ(st) method is statistically consistent in estimating unrooted species trees. The simulation results suggest that NJ(st) and STAR (another coalescence-based method for inferring species trees) perform almost equally well in estimating topologies of species trees, whereas the Bayesian coalescence-based method, BEST, outperforms both NJ(st) and STAR. Unlike BEST and STAR, the NJ(st) method can take unrooted gene trees to infer species trees without using an outgroup. In addition, the NJ(st) method can handle missing data and is thus useful in phylogenomic studies in which data sets often contain missing loci for some individuals. PMID:21447481

Liu, Liang; Yu, Lili

2011-10-01

112

Anti-oxidant and natural killer cell activity of Korean red ginseng (Panax ginseng) and urushiol (Rhus vernicifera Stokes) on non-alcoholic fatty liver disease of rat.  

PubMed

Anti-oxidative and immunologic effects of the Korea red ginseng (KRG; Panax ginseng) and urushiol (Rhus vernicifera Stokes) on non-alcoholic fatty liver disease (NAFLD) were evaluated. Forty-five rats (five Long-Evans Tokushima Otsuka and 40 Otsuka Long-Evans Tokushima Fatty [OLETF] rats) received chew diets for 10months; after this period. The OLETF rats were divided into the following four groups according to diet for 2months: NAFLD (chew), KRG (chew+KRG [200mg/kg/day]), urushiol (chew+urushiol [0.5mg/kg/day]), and ursodeoxycholic acid (UDCA) (chew+UDCA [15mg/kg/day]) groups. Liver function, lipid profiles and anti-oxidant activity of liver and serum, natural killer (NK) cell activity, and pathology were compared. In KRG and urushiol groups, the level of serum triglyceride ([302.0±70.4 and 275.2±63.8] vs. 527.7±153.3mg/dL) were lower compared with that of NAFLD group (p<0.05). The levels of HDL-cholesterol (liver tissue: [4.8±0.2 and 4.8±0.5] vs. 4.2±0.2mg/g) and NK cell activity ([3485±910 and 3559±910] vs. 2486±619 counts) were significantly higher than those of the NAFLD group (p<0.001). Inflammation with neutrophil infiltration was observed in only two rats in the NAFLD group. These results suggest that 2months of oral KRG or urushiol administration improves lipid profiles and stimulates NK cell activity, while inhibiting steatohepatitis in OLEFT rats. PMID:23369934

Hong, So Hyung; Suk, Ki Tae; Choi, Sang Hyeon; Lee, Jung Wook; Sung, Ho Taik; Kim, Chang Hoon; Kim, Eun Ji; Kim, Myoung Jo; Han, Sang Hak; Kim, Moon Young; Baik, Soon Koo; Kim, Dong Joon; Lee, Gyoung-Ja; Lee, Sang-Kyu; Park, Seung Ha; Ryu, Ohk Hyun

2013-05-01

113

Anti-inflammatory effects of sulfuretin from Rhus verniciflua Stokes via the induction of heme oxygenase-1 expression in murine macrophages.  

PubMed

Rhus verniciflua Stokes (Anacardiaceae) has traditionally been used as an ingredient in East Asian medicines used to treat oxidative damage and cancer. Sulfuretin is one of the major flavonoid components isolated from R. verniciflua. In the present study, we isolated sulfuretin from R. verniciflua and demonstrated that sulfuretin inhibited inducible nitric oxide synthase (iNOS) protein and mRNA expression, reduced iNOS-derived NO, suppressed COX-2 protein and mRNA expression, and reduced COX-derived PGE(2) production in lipopolysaccharide (LPS)-stimulated RAW264.7 and murine peritoneal macrophages. Similarly, sulfuretin reduced tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) production. In addition, sulfuretin suppressed the phosphorylation and degradation of I kappaB-alpha as well as the nuclear translocation of p65 by the stimulation of LPS in RAW264.7 macrophages. Furthermore sulfuretin induced heme oxygenase (HO)-1 expression through nuclear translocation of nuclear factor E2-related factor 2 (Nrf)2 and increased heme oxygenase (HO) activity in RAW264.7 macrophages. The effects of sulfuretin on LPS-induced NO, PGE(2), TNF-alpha, and IL-1 beta production were partially reversed by the HO-1 inhibitor, tin protoporphyrin (SnPP). Therefore, it is suggested that sulfuretin-induced HO-1 expression plays a role of the resulting anti-inflammatory effects in macrophages. This indicated that the anti-inflammatory effects of sulfuretin in macrophages might be exerted through a novel mechanism that involves HO-1 expression. PMID:20450988

Lee, Dong-Sung; Jeong, Gil-Saeng; Li, Bin; Park, Hyun; Kim, Youn-Chul

2010-08-01

114

Categorizing ideas about trees: a tree of trees.  

PubMed

The aim of this study is to explore whether matrices and MP trees used to produce systematic categories of organisms could be useful to produce categories of ideas in history of science. We study the history of the use of trees in systematics to represent the diversity of life from 1766 to 1991. We apply to those ideas a method inspired from coding homologous parts of organisms. We discretize conceptual parts of ideas, writings and drawings about trees contained in 41 main writings; we detect shared parts among authors and code them into a 91-characters matrix and use a tree representation to show who shares what with whom. In other words, we propose a hierarchical representation of the shared ideas about trees among authors: this produces a "tree of trees." Then, we categorize schools of tree-representations. Classical schools like "cladists" and "pheneticists" are recovered but others are not: "gradists" are separated into two blocks, one of them being called here "grade theoreticians." We propose new interesting categories like the "buffonian school," the "metaphoricians," and those using "strictly genealogical classifications." We consider that networks are not useful to represent shared ideas at the present step of the study. A cladogram is made for showing who is sharing what with whom, but also heterobathmy and homoplasy of characters. The present cladogram is not modelling processes of transmission of ideas about trees, and here it is mostly used to test for proximity of ideas of the same age and for categorization. PMID:23950877

Fisler, Marie; Lecointre, Guillaume

2013-01-01

115

Categorizing Ideas about Trees: A Tree of Trees  

PubMed Central

The aim of this study is to explore whether matrices and MP trees used to produce systematic categories of organisms could be useful to produce categories of ideas in history of science. We study the history of the use of trees in systematics to represent the diversity of life from 1766 to 1991. We apply to those ideas a method inspired from coding homologous parts of organisms. We discretize conceptual parts of ideas, writings and drawings about trees contained in 41 main writings; we detect shared parts among authors and code them into a 91-characters matrix and use a tree representation to show who shares what with whom. In other words, we propose a hierarchical representation of the shared ideas about trees among authors: this produces a “tree of trees.” Then, we categorize schools of tree-representations. Classical schools like “cladists” and “pheneticists” are recovered but others are not: “gradists” are separated into two blocks, one of them being called here “grade theoreticians.” We propose new interesting categories like the “buffonian school,” the “metaphoricians,” and those using “strictly genealogical classifications.” We consider that networks are not useful to represent shared ideas at the present step of the study. A cladogram is made for showing who is sharing what with whom, but also heterobathmy and homoplasy of characters. The present cladogram is not modelling processes of transmission of ideas about trees, and here it is mostly used to test for proximity of ideas of the same age and for categorization.

Fisler, Marie; Lecointre, Guillaume

2013-01-01

116

Additive similarity trees  

Microsoft Academic Search

Similarity data can be represented by additive trees. In this model, objects are represented by the external nodes of a tree, and the dissimilarity between objects is the length of the path joining them. The additive tree is less restrictive than the ultrametric tree, commonly known as the hierarchical clustering scheme. The two representations are characterized and compared. A computer

Shmuel Sattath; Amos Tversky

1977-01-01

117

Tree Tectonics  

NASA Astrophysics Data System (ADS)

Nature often replicates her processes at different scales of space and time in differing media. Here a tree-trunk cross section I am preparing for a dendrochronological display at the Battle Creek Cypress Swamp Nature Sanctuary (Calvert County, Maryland) dried and cracked in a way that replicates practically all the planform features found along the Mid-Oceanic Ridge (see Figure 1). The left-lateral offset of saw marks, contrasting with the right-lateral ``rift'' offset, even illustrates the distinction between transcurrent (strike-slip) and transform faults, the latter only recognized as a geologic feature, by J. Tuzo Wilson, in 1965. However, wood cracking is but one of many examples of natural processes that replicate one or several elements of lithospheric plate tectonics. Many of these examples occur in everyday venues and thus make great teaching aids, ``teachable'' from primary school to university levels. Plate tectonics, the dominant process of Earth geology, also occurs in miniature on the surface of some lava lakes, and as ``ice plate tectonics'' on our frozen seas and lakes. Ice tectonics also happens at larger spatial and temporal scales on the Jovian moons Europa and perhaps Ganymede. Tabletop plate tectonics, in which a molten-paraffin ``asthenosphere'' is surfaced by a skin of congealing wax ``plates,'' first replicated Mid-Oceanic Ridge type seafloor spreading more than three decades ago. A seismologist (J. Brune, personal communication, 2004) discovered wax plate tectonics by casually and serendipitously pulling a stick across a container of molten wax his wife and daughters had used in making candles. Brune and his student D. Oldenburg followed up and mirabile dictu published the results in Science (178, 301-304).

Vogt, Peter R.

2004-09-01

118

Visibility Representations of Trees.  

National Technical Information Service (NTIS)

Trees are among the most common structures in computing and many algorithms for drawing trees have been developed in the last years. Such algorithms usually adopt different drawing conventions and attempt to solve several optimization problems. The aim of...

G. Kant G. Liotta R. Tamassia I. G. Tollis

1996-01-01

119

Chem-Is-Tree.  

ERIC Educational Resources Information Center

Provides details on the chemical composition of trees including a definition of wood. Also includes an activity on anthocyanins as well as a discussion of the resistance of wood to solvents and chemicals. Lists interesting products from trees. (DDR)

Barry, Dana M.

1997-01-01

120

Tropical Tree Seed Manual.  

National Technical Information Service (NTIS)

The Tropical Tree Seed Manual is a one-volume reference manual for students, technicians, and scientists that provides comprehensive internationally compiled data about tropical trees. The emphasis is on species of the Americas; however, a number of tropi...

J. A. Vozzo

2002-01-01

121

Evolution of tree nutrition.  

PubMed

Using a broad definition of trees, the evolutionary origins of trees in a nutritional context is considered using data from the fossil record and molecular phylogeny. Trees are first known from the Late Devonian about 380 million years ago, originated polyphyletically at the pteridophyte grade of organization; the earliest gymnosperms were trees, and trees are polyphyletic in the angiosperms. Nutrient transporters, assimilatory pathways, homoiohydry (cuticle, intercellular gas spaces, stomata, endohydric water transport systems including xylem and phloem-like tissue) and arbuscular mycorrhizas preceded the origin of trees. Nutritional innovations that began uniquely in trees were the seed habit and, certainly (but not necessarily uniquely) in trees, ectomycorrhizas, cyanobacterial, actinorhizal and rhizobial (Parasponia, some legumes) diazotrophic symbioses and cluster roots. PMID:20581011

Raven, John A; Andrews, Mitchell

2010-09-01

122

Tea tree oil  

MedlinePLUS

... of the nail (onychomycosis), lice, scabies, athlete’s foot (tinea pedis), and ringworm. It is also used topically as ... TEA TREE OIL are as follows:Athlete’s foot (tinea pedis). Topical application of a 10% tea tree oil ...

123

Pine tree forest  

NSDL National Science Digital Library

The pine tree demonstrates the differences among gymnosperms and bryophytes and seedless vascular plants. Pine trees have separate cones with pollen and ovulates. Wind blows the pollen onto the ovulate cone and seeds are produced.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

124

Directed TreeWidth  

Microsoft Academic Search

We generalize the concept of tree-width to directed graphs and prove that every directed graph with no “haven” of large order has small tree-width. Conversely, a digraph with a large haven has large tree-width. We also show that the Hamilton cycle problem and other NP-hard problems can be solved in polynomial time when restricted to digraphs of bounded tree-width.

Thor Johnson; Neil Robertson; Paul D. Seymour; Robin Thomas

2001-01-01

125

Build a Tree  

NSDL National Science Digital Library

This activity (on pages 13-18) has learners build a model tree and then figure out how to make their tree stand up by itself. This illustrates how the tall rain forest trees adapt to support a huge trunk and heavy branches, while also sending their roots out instead of down. Trees built in this activity can be used for the Rain Forest in Your Room activity that is also part of the Wonderwise Rain Forest Ecologist Activity Book.

Museum, University O.; Nebraska Cooperative Extension 4-H Youth Development

2001-01-01

126

Graded Brauer Tree Algebras  

Microsoft Academic Search

In this paper we construct non-negative gradings on a basic Brauer tree algebra $A_{\\\\Gamma}$ corresponding to an arbitrary Brauer tree $\\\\Gamma$ of type $(m,e)$. We do this by transferring gradings via derived equivalence from a basic Brauer tree algebra $A_S$, whose tree is a star with the exceptional vertex in the middle, to $A_{\\\\Gamma}$. The grading on $A_S$ comes from

Dusko Bogdanic

2008-01-01

127

Diary of a Tree.  

ERIC Educational Resources Information Center

Describes an activity to develop students' skills of observation and recordkeeping by studying the growth of a tree's leaves during the spring. Children monitor the growth of 11 tress over a 2-month period, draw pictures of the tree at different stages of growth, and write diaries of the tree's growth. (MDH)

Srulowitz, Frances

1992-01-01

128

Structural Equation Model Trees  

ERIC Educational Resources Information Center

In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree

Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

2013-01-01

129

Nectarine tree, "Kam Red"  

US Patent & Trademark Office Database

A new and distinct nectarine tree denominated varietally as "Kam Red" and generally resembling the Flamekist nectarine tree (unpatented) but bearing a freestone fruit which is mature for harvesting and shipment approximately five to six days earlier than that of the Flamekist nectarine tree in the San Joaquin Valley of Central California.

1989-06-20

130

Macro Tree Transducers  

Microsoft Academic Search

Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical topics like composition, decomposition, domains, and ranges of the induced translation classes. The extension with

Joost Engelfriet; Heiko Vogler

1985-01-01

131

RC trees revisited  

Microsoft Academic Search

RC tree approximation is a computationally simple method for calculating the signal delay of MOS circuits with several states of fanout. The author derives a formal solution of RC tree equations. Based on this solution, it is shown that even though waveforms found using RC tree approximation are inaccurate, delays are exact. The author derives the dependence of the delays

Mehinet A. Cirit

1988-01-01

132

STRESS MANAGEMENT FOR TREES1  

Microsoft Academic Search

Excessive stress is a common cause of tree mor- tality in the urban environment. People must take positive steps to minimize and avoid stress on trees if urban shade trees are to survive and grow. Stress kills trees. However, stress is also part of the environment of all trees and a stress-free con- dition for a tree can only exist

Terry A. Tattar

1983-01-01

133

Growth of a Pine Tree  

ERIC Educational Resources Information Center

The growth of a pine tree is examined by preparing "tree cookies" (cross-sectional disks) between whorls of branches. The use of Christmas trees allows the tree cookies to be obtained with inexpensive, commonly available tools. Students use the tree cookies to investigate the annual growth of the tree and how it corresponds to the number of whorls…

Rollinson, Susan Wells

2012-01-01

134

Reversible adaptive trees.  

PubMed

We describe reversible adaptive trees, a class of stochastic algorithms modified from the formerly described adaptive trees. They evolve in time a finite subset of an ambient Euclidean space of any dimension, starting from a seed point and, accreting points to the evolving set, they grow branches towards a target set which can depend on time. In contrast with plain adaptive trees, which were formerly proven to have strong convergence properties to a static target, the points of reversible adaptive trees are removed from the tree when they have not been used recently enough in a path from the root to an accreted point. This, together with a straightening process performed on the branches, permits the tree to follow some moving targets and still remain adapted to it. We then discuss in what way one can see such reversible trees as a model for a qualitative property of resilience, which leads us to discuss qualitative modeling. PMID:23934230

Kergosien, Yannick L

2013-09-01

135

Ephedra alte (Joint Pine): An Invasive, Problematic Weedy Species in Forestry and Fruit Tree Orchards in Jordan  

PubMed Central

A field survey was carried out to record plant species climbed by Ephedra alte in certain parts of Jordan during 2008–2010. Forty species of shrubs, ornamental, fruit, and forest trees belonging to 24 plant families suffered from the climbing habit of E. alte. Growth of host plants was adversely affected by E. alte growth that extended over their vegetation. In addition to its possible competition for water and nutrients, the extensive growth it forms over host species prevents photosynthesis, smothers growth and makes plants die underneath the extensive cover. However, E. alte did not climb all plant species, indicating a host preference range. Damaged fruit trees included Amygdalus communis, Citrus aurantifolia, Ficus carica, Olea europaea, Opuntia ficus-indica, and Punica granatum. Forestry species that were adversely affected included Acacia cyanophylla, Ceratonia siliqua, Crataegus azarolus, Cupressus sempervirens, Pinus halepensis, Pistacia atlantica, Pistacia palaestina, Quercus coccifera, Quercus infectoria, Retama raetam, Rhamnus palaestina, Rhus tripartita, and Zizyphus spina-christi. Woody ornamentals attacked were Ailanthus altissima, Hedera helix, Jasminum fruticans, Jasminum grandiflorum, Nerium oleander, and Pyracantha coccinea. Results indicated that E. alte is a strong competitive for light and can completely smother plants supporting its growth. A. communis, F. carica, R. palaestina, and C. azarolus were most frequently attacked.

Qasem, Jamal R.

2012-01-01

136

Holiday Factor Trees  

NSDL National Science Digital Library

To review the idea of factor trees and prime factorization I have the students make Holiday Factor Trees. I created a template that looks like a Christmas tree that the students can trace out. We use green paper for the top of the tree and brown paper for the trunk of the tree. Each student then picks a number to find the prime factorization for. It might be helpful to assign each student a number; therefore, they do not all end up doing the same number. I then have the students make a star for the top of their tree which they write their assigned number on. Next, they cut out construction paper bulbs that become the factors on their factor tree. (Pre cut stars and bulbs may be helpful for this as well). You can choose to do any color bulbs, but one thing that I had my student do was to use the same color for the prime numbers at the bottom of the tree therefore prime factors stand out and look unified. On the trunk of the tree the students also wrote the final prime factorization using exponents. Example:1 Yellow Star: 644 multicolored Bulbs: 8, 8,4,46 Red Prime Factors Bulbs: 2,2,2,2,2,2,

2011-12-06

137

Chem-Is-Tree  

NASA Astrophysics Data System (ADS)

Trees are woody plants that contain chemicals and undergo chemical reactions. They consist of cellulose, volatile oils, fatty acids, and more. Wood is obtained from the stems, roots, and branches of trees. It is not a homogeneous material with a uniform structure but instead a tissue of different kinds of cells which perform specific functions in the living plant. Trees are of great importance. They provide oxygen which results from photosynthesis taking place in their leaves. In addition, trees supply us with interesting products such as vanilla flavoring and natural-rubber used in cements, adhesives, vehicle tires and shoes.

Barry, Dana M.

1997-10-01

138

National Register of Big Trees  

NSDL National Science Digital Library

Most trees can outlive us. Even so, it's not unusual for trees to succumb to disease, insects, over development and drought. So it's especially meaningful when a tree reaches a good old age. Here you'll find out all about the oldest trees on earth, as well as have the opportunity to nominate a old tree you might know.

Forests, American

139

Tree Projects for Schools.  

National Technical Information Service (NTIS)

Trees have an enormous educational potential when used as a subject for class projects. This book consists of projects which follow a general theme. The study of a single tree in the school grounds leads on to an examination of basic ecological principles...

R. Webb

1984-01-01

140

Trees From Helicopters  

NSDL National Science Digital Library

This story is aimed at promoting not only inquiry into the germination of tree seeds but seeing trees as typical flowering plants, also known as angiosperms. There is also ample opportunity to take an excursion into fruits and seeds and the germination of

Konicek-Moran, Richard

2008-04-01

141

Trees From Helicopters, Continued  

NSDL National Science Digital Library

Maples are very interesting trees with lots of variation in form. They provide us with a view of diversity in plants as well as a chance to look at natural phenomena that is very common to anyone who has had a maple tree near them. The main purpose is to

Konicek-Moran, Richard

2009-04-01

142

Survival of Trees  

NSDL National Science Digital Library

In this video a scientist explains how DNA extracted from ancient tree remains provides insights about how trees/plants have adapted, over time, to changes in CO2 in the atmosphere. Her lab research investigates changes in plant genotypes under experimental conditions that simulate potential changes in CO2 levels in the future.

Foundation, National S.; Learn, Nbc; Science 360 Network

143

Boosting Lazy Decision Trees  

Microsoft Academic Search

This paper explores the problem of how to construct lazy decision tree ensembles. We present and empirically evaluate a relevance- based boosting-style algorithm that builds a lazy decision tree ensemble customized for each test instance. From the experimental results, we conclude that our boosting-style algorithm signicantly improves the perfor- mance of the base learner. An empirical comparison to boosted regular

Xiaoli Zhang Fern; Carla E. Brodley

2003-01-01

144

Tree Pattern Rewriting Systems  

Microsoft Academic Search

Classical verification often uses abstraction when dealing with data. On the other hand, dynamic XML-based applications have become pervasive, for instance with the ever growing importance of web services. We define here Tree Pattern Rewriting Systems (TPRS) as an abstract model of dynamic XML-based documents. TPRS systems gener- ate infinite transition systems, where states are unranked and unordered trees (hence

Blaise Genest; Anca Muscholl; Olivier Serre; Marc Zeitoun

2008-01-01

145

Biodiversity and Evolutionary Trees  

NSDL National Science Digital Library

In this interactive activity, learners analyze seashells to explore phylogeny and evolution. Learners identify similar and dissimilar seashells to create a phylogenetic tree. The Teacher Guide includes pre-activity video clip suggestions and a pre-activity sorting exercise. The Teacher Guide also includes instructions on how learners can draw a phylogenetic tree instead of using the online interactive.

Institute, Howard H.

2010-01-01

146

Fault tree handbook  

Microsoft Academic Search

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic

D. F. Haasl; N. H. Roberts; W. E. Vesely; F. F. Goldberg

1981-01-01

147

The Flame Tree  

ERIC Educational Resources Information Center

Lewis's own experiences living in Indonesia are fertile ground for telling "a ripping good story," one found in "The Flame Tree." He hopes people will enjoy the tale and appreciate the differences of an unfamiliar culture. The excerpt from "The Flame Tree" will reel readers in quickly.

Lewis, Richard

2004-01-01

148

Phylogenetic trees in bioinformatics  

SciTech Connect

Genetic data is often used to infer evolutionary relationships among a collection of viruses, bacteria, animal or plant species, or other operational taxonomic units (OTU). A phylogenetic tree depicts such relationships and provides a visual representation of the estimated branching order of the OTUs. Tree estimation is unique for several reasons, including: the types of data used to represent each OTU; the use ofprobabilistic nucleotide substitution models; the inference goals involving both tree topology and branch length, and the huge number of possible trees for a given sample of a very modest number of OTUs, which implies that fmding the best tree(s) to describe the genetic data for each OTU is computationally demanding. Bioinformatics is too large a field to review here. We focus on that aspect of bioinformatics that includes study of similarities in genetic data from multiple OTUs. Although research questions are diverse, a common underlying challenge is to estimate the evolutionary history of the OTUs. Therefore, this paper reviews the role of phylogenetic tree estimation in bioinformatics, available methods and software, and identifies areas for additional research and development.

Burr, Tom L [Los Alamos National Laboratory

2008-01-01

149

Global Trees Campaign  

NSDL National Science Digital Library

Along with increasing concerns about the extinction of different animal species, there has been increased interest in monitoring the fate of plant species, particularly those of various trees. Drawing on a partnership between Flora & Fauna International and the UNEP World Conservation Monitoring Centre, the Global Trees Campaign Web site serves as an online conduit for information about endangered tree species. First-time visitors will want to read the various tree profiles along the right-hand side of the homepage. Some of the species covered here include the African blackwood, Honduras rosewood, and the monkey puzzle tree, which grows naturally in Chile and Argentina. The resources section of the site is also worth a look, as it contains a database with information on close to 7,300 tree species, and list of suggested readings -- including several that are available as PDF files. For those interested in the projects initiated by the Global Trees Campaign, a section detailing their various initiatives around the globe is also available for consultation.

150

Landscape in a Lacquer Box  

ERIC Educational Resources Information Center

A symbolic dry landscape garden of Eastern origin holds a special fascination for the author's middle-school students, which is why the author chose to create a project exploring this view of nature. A dry landscape garden, or "karesansui," is an arrangement of rocks, worn by nature and surrounded by a "sea" of sand, raked into patterns…

Savage, Martha

2010-01-01

151

Evolutionary tree reconstruction  

NASA Technical Reports Server (NTRS)

It is described how Minimum Description Length (MDL) can be applied to the problem of DNA and protein evolutionary tree reconstruction. If there is a set of mutations that transform a common ancestor into a set of the known sequences, and this description is shorter than the information to encode the known sequences directly, then strong evidence for an evolutionary relationship has been found. A heuristic algorithm is described that searches for the simplest tree (smallest MDL) that finds close to optimal trees on the test data. Various ways of extending the MDL theory to more complex evolutionary relationships are discussed.

Cheeseman, Peter; Kanefsky, Bob

1990-01-01

152

Learning classification trees  

NASA Technical Reports Server (NTRS)

Algorithms for learning classification trees have had successes in artificial intelligence and statistics over many years. How a tree learning algorithm can be derived from Bayesian decision theory is outlined. This introduces Bayesian techniques for splitting, smoothing, and tree averaging. The splitting rule turns out to be similar to Quinlan's information gain splitting rule, while smoothing and averaging replace pruning. Comparative experiments with reimplementations of a minimum encoding approach, Quinlan's C4 and Breiman et al. Cart show the full Bayesian algorithm is consistently as good, or more accurate than these other approaches though at a computational price.

Buntine, Wray

1991-01-01

153

Trees of trees: an approach to comparing multiple alternative phylogenies.  

PubMed

Phylogenetic analysis very commonly produces several alternative trees for a given fixed set of taxa. For example, different sets of orthologous genes may be analyzed, or the analysis may sample from a distribution of probable trees. This article describes an approach to comparing and visualizing multiple alternative phylogenies via the idea of a "tree of trees" or "meta-tree." A meta-tree clusters phylogenies with similar topologies together in the same way that a phylogeny clusters species with similar DNA sequences. Leaf nodes on a meta-tree correspond to the original set of phylogenies given by some analysis, whereas interior nodes correspond to certain consensus topologies. The construction of meta-trees is motivated by analogy with construction of a most parsimonious tree for DNA data, but instead of using DNA letters, in a meta-tree the characters are partitions or splits of the set of taxa. An efficient algorithm for meta-tree construction is described that makes use of a known relationship between the majority consensus and parsimony in terms of gain and loss of splits. To illustrate these ideas meta-trees are constructed for two datasets: a set of gene trees for species of yeast and trees from a bootstrap analysis of a set of gene trees in ray-finned fish. A software tool for constructing meta-trees and comparing alternative phylogenies is available online, and the source code can be obtained from the author. PMID:18853364

Nye, Tom M W

2008-10-01

154

Generalized constructive tree weights  

NASA Astrophysics Data System (ADS)

The Loop Vertex Expansion (LVE) is a quantum field theory (QFT) method which explicitly computes the Borel sum of Feynman perturbation series. This LVE relies in a crucial way on symmetric tree weights which define a measure on the set of spanning trees of any connected graph. In this paper we generalize this method by defining new tree weights. They depend on the choice of a partition of a set of vertices of the graph, and when the partition is non-trivial, they are no longer symmetric under permutation of vertices. Nevertheless we prove they have the required positivity property to lead to a convergent LVE; in fact we formulate this positivity property precisely for the first time. Our generalized tree weights are inspired by the Brydges-Battle-Federbush work on cluster expansions and could be particularly suited to the computation of connected functions in QFT. Several concrete examples are explicitly given.

Rivasseau, Vincent; Tanasa, Adrian

2014-04-01

155

The Tree of Life  

NSDL National Science Digital Library

This article describes how interdisciplinary, thematic lessons about plants, animals, and the environment were introduced with children's literature. First-grade students created a display of the African baobab tree and its inhabitants, focusing on their interdependence.

Plummer, Donna M.; Macshara, Jeannie; Brown, Skila K.

2003-03-01

156

Encoding Voxel Trees.  

National Technical Information Service (NTIS)

The paper presents an analysis based on geometric probability for obtaining a better understanding of the space efficiency of representing three dimensional pictures using voxel trees. It is shown that asymptotically, as resolution is increased with respe...

W. de Jonge A. Schijf E. Wattel

1991-01-01

157

Trees as energy crops  

SciTech Connect

A report is presented of studies on the energy production of forest trees in California. The volume yield of the fastest growing species (Eucalyptus) was 23 cubic metres per hectare and energy yield 20 million kcal per hectare per annum.

Standiford, R.B.; Donaldson, D.R.

1982-01-01

158

Tea Tree Oil  

MedlinePLUS

... resistant Staphylococcus aureus (MRSA). However, large, well-designed clinical trials on tea tree oil are lacking, and ... strains of bacteria in people. Some smaller-scale clinical studies have had positive results for treating athlete's ...

159

Life of a Tree  

NSDL National Science Digital Library

In this interactive activity adapted from the National Arbor Day Foundation, take a sixty-two-year journey observing the inner layers, rings, and environmental factors that affect a tree's growth and life cycle.

Foundation, Wgbh E.

2007-08-09

160

Tea tree oil.  

PubMed

Tea tree oil is an increasingly popular ingredient in a variety of household and cosmetic products, including shampoos, massage oils, skin and nail creams, and laundry detergents. Known for its potential antiseptic properties, it has been shown to be active against a variety of bacteria, fungi, viruses, and mites. The oil is extracted from the leaves of the tea tree via steam distillation. This essential oil possesses a sharp camphoraceous odor followed by a menthol-like cooling sensation. Most commonly an ingredient in topical products, it is used at a concentration of 5% to 10%. Even at this concentration, it has been reported to induce contact sensitization and allergic contact dermatitis reactions. In 1999, tea tree oil was added to the North American Contact Dermatitis Group screening panel. The latest prevalence rates suggest that 1.4% of patients referred for patch testing had a positive reaction to tea tree oil. PMID:22653070

Larson, David; Jacob, Sharon E

2012-01-01

161

Tree of Hexagons  

NSDL National Science Digital Library

In this activity students use measuring skills and follow directions to make a three-dimensional ornament. Learners construct hexagons of graduated sizes from circles and assemble them into a tree. Complete instructions are provided.

2011-01-01

162

The Average Height of Binary Trees and Other Simple Trees  

Microsoft Academic Search

The average height of a binary tree with n internal nodes is shown to be asymptotic to 2 6. This represents the average stack height of the simplest recursive tree traversal algorithm. The method used in this estimation is also applicable to the analysis of traversal algorithms of unary-binary trees, unbalanced 2-3 trees, t-ary trees for any t, and other

Philippe Flajolet; Andrew M. Odlyzko

1982-01-01

163

TreeVector: Scalable, Interactive, Phylogenetic Trees for the Web  

Microsoft Academic Search

BackgroundPhylogenetic trees are complex data forms that need to be graphically displayed to be human-readable. Traditional techniques of plotting phylogenetic trees focus on rendering a single static image, but increases in the production of biological data and large-scale analyses demand scalable, browsable, and interactive trees.Methodology\\/Principal FindingsWe introduce TreeVector, a Scalable Vector Graphics–and Java-based method that allows trees to be integrated

Ralph Pethica; Gary Barker; Tim Kovacs; Julian Gough; I. King Jordan

2010-01-01

164

TreeVector: Scalable, Interactive, Phylogenetic Trees for the Web  

Microsoft Academic Search

Background: Phylogenetic trees are complex data forms that need to be graphically displayed to be human-readable. Traditional techniques of plotting phylogenetic trees focus on rendering a single static image, but increases in the production of biological data and large-scale analyses demand scalable, browsable, and interactive trees. Methodology\\/Principal Findings: We introduce TreeVector, a Scalable Vector Graphics-and Java-based method that allows trees

Ralph Pethica; Gary Barker; Tim Kovacs; Julian Gough

2010-01-01

165

Partial Alphabetic Trees  

Microsoft Academic Search

In the partial alphabetic tree problem we are given a multiset of nonnegative weights W = w\\u000a 1, . . . , w\\u000a \\u000a n\\u000a , partitioned into k ? n blocks B\\u000a 1, . . . , B\\u000a k. We want to find a binary tree T where the elements of W resides in its leaves such that if we

Arye Barkan; Haim Kaplan

2002-01-01

166

Trees for reclamation  

SciTech Connect

Land reclamation programs sponsored by several state forestry organizations are summarized in these presentations. The use of trees as a preferred specie for revegetation of surface mined lands is addressed. Modern methods of forestry can be used to make land economically and aesthetically acceptable. Tree planting techniques are presented and the role of Mycorrhizae is discussed. There are 30 papers included in this proceedings. States represented include: Alabama, Arkansas, Georgia, Illinois, Kansas, Kentucky, Maryland, Virginia, Iowa, Ohio, Pennsylvania, and West Virginia.

Not Available

1980-01-01

167

Handy Family Tree  

NSDL National Science Digital Library

In this bilingual (English/Spanish) activity, learners create family trees by tracing the hands of their family members. Learners list inherited traits like eye color, freckles, and chin shape on the fingers of the left hands and list learned traits like favorite foods, games, and pets on the fingers of the right hands. Learners assemble the hands to form trees. Use this family activity to help learners distinguish between inherited and learned traits.

Utah, University O.

2006-01-01

168

Tree nut allergy  

Microsoft Academic Search

Tree nuts are clinically associated with severe immunoglobulin E-mediated systemic allergic reactions independent of pollen\\u000a allergy and with reactions that are usually confined to the oral mucosa in patients with immunoglobulin E directed toward\\u000a cross-reacting pollen allergens. The latter reactions can progress to severe and life-threatening episodes in some patients.\\u000a Many patients with severe tree nut allergy are co-sensitized to

Suzanne S. Teuber; Sarah S. Comstock; Shridhar K. Sathe; Kenneth H. Roux

2003-01-01

169

State Trees and Arbor Days.  

ERIC Educational Resources Information Center

Provides information on state trees for each of the 50 states and the District of Columbia. Includes for each state: (1) year in which state tree was chosen; (2) common and scientific names of the tree; (3) arbor day observance; (4) address of state forester; and (5) drawings of the tree, leaf, and fruit or cone. (JN)

Forest Service (USDA), Washington, DC.

170

Image Segmentation with Directed Trees  

Microsoft Academic Search

This correspondence presents a simple algorithm to detect and label homogeneous areas in an image, using directed trees for region labeling. The scheme constructs directed trees with the image points as nodes, guided by an edge value computed at every point. These directed trees segment the image into disjoint regions. Because of a valley seeldng property of the tree construction

P. M. Narendra; M. Goldberg

1980-01-01

171

Carbon Sequestration in Campus Trees  

NSDL National Science Digital Library

In this activity, students use a spreadsheet to calculate the net carbon sequestration in a set of trees; they will utilize an allometric approach based upon parameters measured on the individual trees. They determine the species of trees in the set, measure trunk diameter at a particular height, and use the spreadsheet to calculate carbon content of the tree using forestry research data.

Cole, Robert S.; Spreadsheets Across the Curruculum; Washington Center; Science Education Resource Center (SERC)

172

Quantum computation and decision trees  

Microsoft Academic Search

Many interesting computational problems can be reformulated in terms of decision trees. A natural classical algorithm is to then run a random walk on the tree, starting at the root, to see if the tree contains a node n level from the root. We devise a quantum-mechanical algorithm that evolves a state, initially localized at the root, through the tree.

Edward Farhi; Sam Gutmann

1998-01-01

173

Random Sampling from B+ Trees  

Microsoft Academic Search

We consider the design and analysis of algorithms to retrieve simple random samples from databases. Specifi- cally, we examine simple random sampling from B+ tree files. Existing methods of sampling from B+ trees, re- quire the use of auxiliary rank information in the nodes of the tree. Such modified B+ tree files are called \\

Frank Olken; Doron Rotem

1989-01-01

174

Isolation and structural characterization of unusual pyranoanthocyanins and related anthocyanins from Staghorn sumac (Rhus typhina L.) via UPLC-ESI-MS, (1)H, (13)C, and 2D NMR spectroscopy.  

PubMed

The six major anthocyanins found in the burgundy coloured fruits of Staghorn sumac (Rhus typhina L.) were isolated and the structures of four compounds were determined by NMR spectroscopic methods as being: 7-O-methyl-delphinidin-3-O-(2?galloyl)-?-d-galactopyranoside; 7-O-methyl-cyanidin-3-O-(2?galloyl)-?-d-galactopyranoside; 7-O-methyl-delphinidin-3-O-(2?'galloyl)-?-d-galactopyranoside-4-vinyl-catechol-3?-O-?-d-glucopyranoside; and 7-O-methyl-cyanidin-3-O-(2?'galloyl)-?-d-galactopyranoside-4-vinyl-catechol-3?-O-?-d-glucopyranoside, respectively. Additionally, two related anthocyanin compounds, cyanidin-3-O-(2?galloyl)-?-d-galactopyranoside and 7-O-methyl-cyanidin-3-O-?-d-galactopyranoside were also recovered, with NMR spectroscopic values closely matching previous reports from other plant species. The prevalence of 7-O-methyl anthocyanins and their galloylated derivatives in sumac is highly unusual, and warrants special attention. Additionally, the in planta occurrence of two 7-O-methyl-pyranoanothocyanin-vinyl-catechol aglycones, Sumadin A and Sumadin B, and their derivatives is noted. To our knowledge, E-ring glycosylated vinyl-catechol pyranoanthocyanins were previously unknown. PMID:23850248

Kirby, Christopher W; Wu, Tao; Tsao, Rong; McCallum, Jason L

2013-10-01

175

Oscillation damping in trees.  

PubMed

Oscillation damping is of vital importance for trees to withstand strong gusty winds. Tree adaptation to wind loading takes place over a long time and during a storm only passive damping mechanisms can reduce the impact of the wind on trunk and roots. Structural damping, a phenomenon, which is associated with the conspicuous movements of the branches relative to the trunk is of particular importance. Primary and higher order branches can be seen as multiple tuned mass dampers. Moreover, as the frequency bands overlap within branches and between primary branches and the entire tree, resonance energy transfer can distribute mechanical energy over the entire tree, such that it is dissipated more effectively than in a tree with stiff branches and not so much focused on the tree trunk and the roots. Theoretical studies using modal analysis and finite element methods have supported these assertions. Next to "multiple mass damping" and "multiple resonance damping", both characterized by linear coupling between the elements, a third non linear mode, operative at large amplitudes has been identified: "damping by branching". In all these not mutually exclusive concepts frequency tuning between the elements appears to be a fundamental requisite. PMID:23602100

Spatz, Hanns-Christof; Theckes, Benoit

2013-06-01

176

Tree domestication in tropical agroforestry  

Microsoft Academic Search

We execute tree ‘domestication’ as a farmer-driven and market-led process, which matches the intraspecific diversity of locally\\u000a important trees to the needs of subsistence farmers, product markets, and agricultural environments. We propose that the products\\u000a of such domesticated trees are called Agroforestry Tree Products (AFTPs) to distinguish them from the extractive tree resources\\u000a commonly referred to as non-timber forest products

A. J. Simons; R. R. B. Leakey

2004-01-01

177

Extracting Species Trees From Complex Gene Trees: Reconciled Trees And Vertebrate Phylogeny  

Microsoft Academic Search

Paralogy is a pervasive problem in trying to use nuclear gene sequences to infer species phylogenies. One strategy for dealing with this problem is to infer species phylogenies from gene trees using reconciled trees, rather than directly from the sequences themselves. In this approach, the optimal species tree is the tree that requires the fewest gene duplications to be invoked.

Roderic D. M. Page

2000-01-01

178

Gene tree correction for reconciliation and species tree inference  

PubMed Central

Background Reconciliation is the commonly used method for inferring the evolutionary scenario for a gene family. It consists in “embedding” inferred gene trees into a known species tree, revealing the evolution of the gene family by duplications and losses. When a species tree is not known, a natural algorithmic problem is to infer a species tree from a set of gene trees, such that the corresponding reconciliation minimizes the number of duplications and/or losses. The main drawback of reconciliation is that the inferred evolutionary scenario is strongly dependent on the considered gene trees, as few misplaced leaves may lead to a completely different history, with significantly more duplications and losses. Results In this paper, we take advantage of certain gene trees’ properties in order to preprocess them for reconciliation or species tree inference. We flag certain duplication vertices of a gene tree, the “non-apparent duplication” (NAD) vertices, as resulting from the misplacement of leaves. In the case of species tree inference, we develop a polynomial-time heuristic for removing the minimum number of species leading to a set of gene trees that exhibit no NAD vertices with respect to at least one species tree. In the case of reconciliation, we consider the optimization problem of removing the minimum number of leaves or species leading to a tree without any NAD vertex. We develop a polynomial-time algorithm that is exact for two special classes of gene trees, and show a good performance on simulated data sets in the general case.

2012-01-01

179

Tree Rings: Timekeepers of the Past.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree

Phipps, R. L.; McGowan, J.

180

Tree Impact Study  

NSDL National Science Digital Library

In this field activity, students document examine the role of a tree in its ecosystem and as part of the environment in a human community. Students measure the tree's dimensions, examine co-residing organisms, leaf litter, and soil, and research the tree's history, using interviews or archival resources. A measuring stick, sturdy string, and an outdoor thermometer are required. An art project concludes the exploration. This activity is supported by a textbook chapter, "A History of Forest use in the Pacific Northwest,â part of the unit, A New World View, in Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

181

Trees and Carbon  

NSDL National Science Digital Library

The transport and transformation of substances in the environment are known collectively as biogeochemical cycles. These global cycles involve the circulation of elements and nutrients that sustain both the biological and physical aspects of the environment. As an example, this discussion centers around the carbon cycle and how carbon is sequestered in trees. Students will perform an activity that replicates a case study in which the biomass of trees in a 15-acre plot of forest was calculated to determine the amount of carbon sequestered per acre.

Pratte, John

182

VisTree: Generic Decision Tree Inducer and Visualizer  

Microsoft Academic Search

\\u000a Decision tree is one of the most popular and commonly used technique for predictive modeling. Interpretability and understandability\\u000a makes decision trees an attractive option among various classification induction algorithms. There are several freewares available\\u000a for decision tree induction which can be used in data mining education and practice. However, these freewares have limited\\u000a capability to interactively visualize the induced tree

Vasudha Bhatnagar; Eman Zaman; Yayati Rajpal; Manju Bhardwaj

2010-01-01

183

Bkd-Tree: A Dznamic Scalable kd-Tree  

Microsoft Academic Search

Abstract In this paper we propose a new data structure, called the Bkd - tree, for indexing large multi - dimensional point data sets The Bkd - tree is an I\\/O - efficient dynamic data structure based on the kd - tree We present the results of an extensive experimental study showing that unlike previous attempts on making external versions

Octavian Procopiuc; Pankaj K. Agarwal; Lars Arge; Jeffrey Scott Vitter

2003-01-01

184

Flat Tree Oyster (Isognomon alatus)  

USGS Multimedia Gallery

At high tide, the red bark of the Red Mangrove Trees is submerged, creating a brilliant reflection at the water's surface. Flat Tree Oysters (Isognomon alatus) grow on the upper portions of the roots....

2010-05-03

185

An Introduction to Tree Diagrams  

NSDL National Science Digital Library

This brief article describes the use of tree diagrams in calculating probabilities. The author provides examples of how tree diagrams are used to calculate specific probabilities and why the language chosen relates to the operations used to find the probability.

Cork, Stu

2014-01-01

186

Selecting Superior Yellow Birch Trees.  

National Technical Information Service (NTIS)

The report describes procedures to follow and characteristics to consider in selecting superior yellow birch trees. The first selection should be on the basis of tree quality. Characteristics to consider are as follows: for the stem - straightness, roundn...

K. E. Clausen R. M. Godman

1967-01-01

187

Measure a Tree  

NSDL National Science Digital Library

This activity introduces measurement and scale using hands-on activities. In this activity, students use the concept of similar triangles to determine the height of a tree. This activity is one of several available on an educational poster related to NASA's Space Interferometry Mission.

188

Formal Fault Tree Semantics  

Microsoft Academic Search

In train control systems, more and more (electro-)mechanical devices are substituted by software based devices. To sustain the high level safety standards for these embedded systems, we propose the integration of fault tree analysis and formal methods. This combines two important safety analysis methods from the involved domains of engineering and software development. Our approach proposes to build a formal

Gerhard Schellhorn; Andreas Thums; Wolfgang Reif Lehrstuhl

2002-01-01

189

Christmas Tree Category Manual.  

ERIC Educational Resources Information Center

This manual provides information needed to meet the standards for pesticide applicator certification. Pests and diseases of christmas tree plantations are identified and discussed. Section one deals with weeds and woody plants and the application, formulation and effects of herbicides in controlling them. Section two discusses specific diseases…

Bowman, James S.; Turmel, Jon P.

190

Cherry Trees with Cones?  

Microsoft Academic Search

Statistics students and practitioners may think that they can get away with doing individual t tests instead of a simultaneous test provided that the t values look “insignificant” enough. The trees data set from the Minitab Handbook provides a multiple regression example illustrating how this shortcut can lead to trouble.

David Fairley

1986-01-01

191

DRAFT Wrapping of Trees  

Microsoft Academic Search

We explore the descriptive power, in terms of syn- tactic phenomena, of a formalism that extends Tree- Adjoining Grammar (TAG) by adding a fourth level of hierarchical decomposition to the three levels TAG already employs. While extending the descrip- tive power minimally, the additional level of decom- position allows us to obtain a uniform account of a range of phenomena

James Rogers

192

Giant Sequoia Tree  

NSDL National Science Digital Library

The purpose of this assessment probe is to elicit students' ideas about transformation of matter. The probe is designed to reveal whether students recognize that a gas from the air (carbon dioxide) is combined with water and transformed into the new material that makes up most of the matter of the tree.

Eberle, Francis; Tugel, Joyce; Keeley, Page

2007-01-01

193

Digging Deeper with Trees.  

ERIC Educational Resources Information Center

Describes hands-on science areas that focus on trees. A project on leaf pigmentation involves putting crushed leaves in a test tube with solvent acetone to dissolve pigment. In another project, students learn taxonomy by sorting and classifying leaves based on observable characteristics. Includes a language arts connection. (PVD)

Growing Ideas, 2001

2001-01-01

194

Tree Nut Allergens  

Microsoft Academic Search

Allergic reactions to tree nuts can be serious and life threatening. Considerable research has been conducted in recent years in an attempt to characterize those allergens that are most responsible for allergy sensitization and triggering. Both native and recombinant nut allergens have been identified and characterized and, for some, the IgE-reactive epitopes described. Some allergens, such as lipid transfer proteins,

Kenneth H. Roux; Suzanne S. Teuber; Shridhar K. Sathe

2003-01-01

195

X-Ray absorption edge determination of the oxidation state and coordination number of copper: application to the type 3 site in rhus vernicifera laccase and its reaction with oxygen  

SciTech Connect

Cu X-ray absorption edge features of 19 Cu(I) and 40 Cu(II) model complexes have been systematically studied and correlated with oxidation state and geometry. Studies of Cu(I) model complexes with different coordination number reveal that an 8983-8984-eV peak (assigned as the Cu 1s ..-->.. 4p transition) can be correlated in energy, shape, and intensity with ligation and site geometry of the cuprous ion. These Cu(I) edge features have been qualitatively interpreted with ligand field concepts. Alternatively, no Cu(II) complex exhibits a peak below 8985.0 eV. The limited intensity observed in the 8983-8985-eV region for some Cu(II) complexes is associated with the tail of an absorption peak at approx. 8986 eV which is affected by the covalency of the equatorial ligands. These models studies allow accurate calibration of a normalized difference edge procedure which is used for the quantitative determination of Cu(I) content in copper complexes of mixed oxidation state composition. This normalized difference edge analysis is then used to quantitatively determine the oxidation states of the copper sites in type 2 copper-depleted (T2D) and native forms of the multicopper oxidase, Rhus vernicifera laccase. The type 3 site of the T2D laccase is found to be fully reduced and stable to oxidation by O/sub 2/ or by 25-fold protein equivalents of ferricyanide, but it can be oxidized by reaction with peroxide. The increase in intensity of the 330-nm absorption feature which results from peroxide titration of T2D laccase is found to correlate linearly with the percent of oxidation of the binuclear copper site.

Kau, L.S.; Spira-Solomon, D.J.; Penner-Hahn, J.E.; Hodgson, K.O.; Solomon, E.I.

1987-10-14

196

Generating functions for generating trees  

Microsoft Academic Search

Certain families of combinatorial objects admit recursive descriptions in terms of gen- erating trees: each node of the tree corresponds to an object, and the branch leading to the node encodes the choices made in the construction of the object. Generating trees lead to a fast computation of enumeration sequences (sometimes, to explicit formulae as well) and provide efficient random

Cyril Banderier; Mireille Bousquet-mélou; Alain Denise; Philippe Flajolet; Danièle Gardy; Dominique Gouyou-beauchamps

2002-01-01

197

New Life From Dead Trees  

ERIC Educational Resources Information Center

There are numerous bird species that will nest only in dead or dying trees. Current forestry practices include clearing forests of these snags, or dead trees. This practice is driving many species out of the forests. An illustrated example of bird succession in and on a tree is given. (MA)

DeGraaf, Richard M.

1978-01-01

198

Bkd-Tree: A Dynamic Scalable kd-Tree  

Microsoft Academic Search

\\u000a In this paper we propose a new index structure, called the Bkd-tree, for indexing large multi-dimensional point data sets.\\u000a The Bkd-tree is an I\\/O-efficient dynamic data structure based on the kd-tree. We present the results of an extensive experimental\\u000a study showing that unlike previous attempts on making external versions of the kd-tree dynamic, the Bkd-tree maintains its\\u000a high space utilization

Octavian Procopiuc; Pankaj K. Agarwal; Lars Arge; Jeffrey Scott Vitter

199

Geometric tree kernels: classification of COPD from airway tree geometry.  

PubMed

Methodological contributions: This paper introduces a family of kernels for analyzing (anatomical) trees endowed with vector valued measurements made along the tree. While state-of-the-art graph and tree kernels use combinatorial tree/graph structure with discrete node and edge labels, the kernels presented in this paper can include geometric information such as branch shape, branch radius or other vector valued properties. In addition to being flexible in their ability to model different types of attributes, the presented kernels are computationally efficient and some of them can easily be computed for large datasets (N - 10.000) of trees with 30 - 600 branches. Combining the kernels with standard machine learning tools enables us to analyze the relation between disease and anatomical tree structure and geometry. Experimental results: The kernels are used to compare airway trees segmented from low-dose CT, endowed with branch shape descriptors and airway wall area percentage measurements made along the tree. Using kernelized hypothesis testing we show that the geometric airway trees are significantly differently distributed in patients with Chronic Obstructive Pulmonary Disease (COPD) than in healthy individuals. The geometric tree kernels also give a significant increase in the classification accuracy of COPD from geometric tree structure endowed with airway wall thickness measurements in comparison with state-of-the-art methods, giving further insight into the relationship between airway wall thickness and COPD. Software: Software for computing kernels and statistical tests is available at http://image.diku.dk/aasa/software.php. PMID:24683967

Feragen, Aasa; Petersen, Jens; Grimm, Dominik; Dirksen, Asger; Pedersen, Jesper Holst; Borgwardt, Karsten; de Bruijne, Marleen

2013-01-01

200

Binary search trees of bounded balance  

Microsoft Academic Search

A new class of binary search trees, called trees of bounded balance, is introduced. These trees are easy to maintain in their form despite insertions and deletions of nodes, and the search time is only moderately longer than in completely balanced trees. Trees of bounded balance differ from other classes of binary search trees in that they contain a parameter

Jürg Nievergelt; Edward M. Reingold

1972-01-01

201

Neuro-fuzzy decision trees.  

PubMed

Fuzzy decision trees are powerful, top-down, hierarchical search methodology to extract human interpretable classification rules. However, they are often criticized to result in poor learning accuracy. In this paper, we propose Neuro-Fuzzy Decision Trees (N-FDTs); a fuzzy decision tree structure with neural like parameter adaptation strategy. In the forward cycle, we construct fuzzy decision trees using any of the standard induction algorithms like fuzzy ID3. In the feedback cycle, parameters of fuzzy decision trees have been adapted using stochastic gradient descent algorithm by traversing back from leaf to root nodes. With this strategy, during the parameter adaptation stage, we keep the hierarchical structure of fuzzy decision trees intact. The proposed approach of applying backpropagation algorithm directly on the structure of fuzzy decision trees improves its learning accuracy without compromising the comprehensibility (interpretability). The proposed methodology has been validated using computational experiments on real-world datasets. PMID:16496439

Bhatt, Rajen B; Gopal, M

2006-02-01

202

Tree of Life  

NSDL National Science Digital Library

Collaboration by biologists worldwide assembles webpages on diversity of organisms on earth, their evolutionary history, phylogenetic relationships, characteristics. Each group described with introduction, photos, map, key references, important links. Start at Kingdom level and move down to individual species by clicking on branches of the Tree diagram. Designed for biologists familiar with Latin names, but useful for others. Treehouse pages, designed for K-16 learners and teachers, complement technical pages presented elsewhere on the site.

203

Insert tree completion system  

SciTech Connect

This paper outlines the overall project for development and installation of a low-profile, caisson-installed subsea Christmas tree. After various design studies and laboratory and field tests of key components, a system for installation inside a 30-in. conductor was ordered in July 1978 from Cameron Iron Works Inc. The system is designed to have all critical-pressure-containing components below the mudline and, with the reduced profile (height) above seabed, provides for improved safety of satellite underwater wells from damage by anchors, trawl boards, and even icebergs. In addition to the innovative nature of the tree design, the completion includes improved 3 1/2-in. through flowline (TFL) pumpdown completion equipment with deep set safety valves and a dual detachable packer head for simplified workover capability. The all-hydraulic control system incorporates a new design of sequencing valve for both Christmas tree control and remote flowline connection. A semisubmersible drilling rig was used to initiate the first end flowline connection at the wellhead for subsequent tie-in to the prelaid, surface-towed, all-welded subsea pipeline bundle.

Brands, K.W.; Ball, I.G.; Cegielski, E.J.; Gresham, J.S.; Saunders, D.N.

1982-09-01

204

TreeFix: statistically informed gene tree error correction using species trees.  

PubMed

Accurate gene tree reconstruction is a fundamental problem in phylogenetics, with many important applications. However, sequence data alone often lack enough information to confidently support one gene tree topology over many competing alternatives. Here, we present a novel framework for combining sequence data and species tree information, and we describe an implementation of this framework in TreeFix, a new phylogenetic program for improving gene tree reconstructions. Given a gene tree (preferably computed using a maximum-likelihood phylogenetic program), TreeFix finds a "statistically equivalent" gene tree that minimizes a species tree-based cost function. We have applied TreeFix to 2 clades of 12 Drosophila and 16 fungal genomes, as well as to simulated phylogenies and show that it dramatically improves reconstructions compared with current state-of-the-art programs. Given its accuracy, speed, and simplicity, TreeFix should be applicable to a wide range of analyses and have many important implications for future investigations of gene evolution. The source code and a sample data set are available at http://compbio.mit.edu/treefix. PMID:22949484

Wu, Yi-Chieh; Rasmussen, Matthew D; Bansal, Mukul S; Kellis, Manolis

2013-01-01

205

A Novel Approach for Compressing Phylogenetic Trees  

NASA Astrophysics Data System (ADS)

Phylogenetic trees are tree structures that depict relationships between organisms. Popular analysis techniques often produce large collections of candidate trees, which are expensive to store. We introduce TreeZip, a novel algorithm to compress phylogenetic trees based on their shared evolutionary relationships. We evaluate TreeZip's performance on fourteen tree collections ranging from 2,505 trees on 328 taxa to 150,000 trees on 525 taxa corresponding to 0.6 MB to 434 MB in storage. Our results show that TreeZip is very effective, typically compressing a tree file to less than 2% of its original size. When coupled with standard compression methods such as 7zip, TreeZip can compress a file to less than 1% of its original size. Our results strongly suggest that TreeZip is very effective at compressing phylogenetic trees, which allows for easier exchange of data with colleagues around the world.

Matthews, Suzanne J.; Sul, Seung-Jin; Williams, Tiffani L.

206

From event-labeled gene trees to species trees  

PubMed Central

Background Tree reconciliation problems have long been studied in phylogenetics. A particular variant of the reconciliation problem for a gene tree T and a species tree S assumes that for each interior vertex x of T it is known whether x represents a speciation or a duplication. This problem appears in the context of analyzing orthology data. Results We show that S is a species tree for T if and only if S displays all rooted triples of T that have three distinct species as their leaves and are rooted in a speciation vertex. A valid reconciliation map can then be found in polynomial time. Simulated data shows that the event-labeled gene trees convey a large amount of information on underlying species trees, even for a large percentage of losses. Conclusions The knowledge of event labels in a gene tree strongly constrains the possible species tree and, for a given species tree, also the possible reconciliation maps. Nevertheless, many degrees of freedom remain in the space of feasible solutions. In order to disambiguate the alternative solutions additional external constraints as well as optimization criteria could be employed.

2012-01-01

207

Alignment of Trees - An Alternative to Tree Edit  

Microsoft Academic Search

In this paper, we propose the alignment of trees as a measure of the similarity between two labeled trees. Both ordered and unordered trees are considered. An algorithm is designed for ordered trees. The time complexity of this algorithm is O(¦T\\u000a1¦· s¦T\\u000a2· (deg(T\\u000a1) + deg(T\\u000a2))2), where ¦T\\u000ai¦ is the number of nodes in T\\u000a\\u000ai

Tao Jiang; Lusheng Wang; Kaizhong Zhang

1994-01-01

208

Exploring Trees and Ponds  

NSDL National Science Digital Library

Trees and Ponds is a collection of activities to be implemented with middle school youth in out-of-school environments. The website provides a rationale and goal of the activities, curriculum activities and resources such as relevant digital photos. Available for free as downloadable PDFs, these activities provide a structure for youth in out-of-school programs to carry out long-term observations of natural objects. This project uses a qualitative approach, where changes over time are studied, recorded (by youth through writing, drawing, and digital photography), and discussed.

209

Redrawing Humanity's Family Tree  

NSDL National Science Digital Library

This New York Times article details two skulls, one from central Africa and the other from the Black Sea republic of Georgia, that "have shaken the human family tree to its roots, sending scientists scrambling to see if their favorite theories are among the fallen fruit." The article discusses how the two skulls have caused scientists to rethink not only how we conceive of human evolution and its chain of events, but even the geography of evolution and migration patterns of very early humans.

Wilford, John N.

1969-12-31

210

Clustering with shallow trees  

NASA Astrophysics Data System (ADS)

We propose a new method for obtaining hierarchical clustering based on the optimization of a cost function over trees of limited depth, and we derive a message-passing method that allows one to use it efficiently. The method and the associated algorithm can be interpreted as a natural interpolation between two well-known approaches, namely that of single linkage and the recently presented affinity propagation. We analyse using this general scheme three biological/medical structured data sets (human population based on genetic information, proteins based on sequences and verbal autopsies) and show that the interpolation technique provides new insight.

Bailly-Bechet, M.; Bradde, S.; Braunstein, A.; Flaxman, A.; Foini, L.; Zecchina, R.

2009-12-01

211

Project Learning Tree  

NSDL National Science Digital Library

Project Learning Tree is a national environmental education program containing a series of learning modules with inquiry-oriented activities for K-12 students and educators that address current environmental topics and issues. These topics range from forests, wildlife and water to community planning, waste management and energy. The materials correlate with the national environmental education performance standards. The curriculum is available for a fee; materials must be ordered or obtained by attending a professional development workshop. The newsletter and an environmental action project guide are free.

212

A Tree of Genetic Traits  

NSDL National Science Digital Library

Learners mark their traits for tongue rolling, PTC tasting (a harmless, bitter chemical), and earlobe attachment on tree leaf cut-outs. They then place their leaves on a large tree with branches, in which each each branch represents a different combination of traits. When completed, the tree forms a visual representation of the frequency of trait combinations within the group. Included are handouts in English and Spanish. This resource also contains information about PTC safety.

Malone, Molly; Starr, Harmony; Mitchell, April

2006-01-01

213

Decision trees: a recent overview  

Microsoft Academic Search

Decision tree techniques have been widely used to build classification models as such models closely resemble human reasoning\\u000a and are easy to understand. This paper describes basic decision tree issues and current research points. Of course, a single\\u000a article cannot be a complete review of all algorithms (also known induction classification trees), yet we hope that the references\\u000a cited will

S. B. Kotsiantis

214

Fault trees and sequence dependencies  

Microsoft Academic Search

One of the frequency cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated

Joanne Bechta Dugan; Salvatore J. Bavuso; Mark A. Boyd

1990-01-01

215

Compositional Temporal Fault Tree Analysis  

Microsoft Academic Search

HiP-HOPS (Hierarchically-Performed Hazard Origin and Propaga- tion Studies) is a recent technique that partly automates Fault Tree Analysis (FTA) by constructing fault trees from system topologies annotated with component-level failure specifications. HiP-HOPS has hitherto created only classical combinatorial fault trees that fail to capture the often significant temporal ordering of failure events. In this paper, we propose temporal extensions to

Martin Walker; Leonardo Bottaci; Yiannis Papadopoulos

2007-01-01

216

Human decision error (HUMDEE) trees  

SciTech Connect

Graphical presentations of human actions in incident and accident sequences have been used for many years. However, for the most part, human decision making has been underrepresented in these trees. This paper presents a method of incorporating the human decision process into graphical presentations of incident/accident sequences. This presentation is in the form of logic trees. These trees are called Human Decision Error Trees or HUMDEE for short. The primary benefit of HUMDEE trees is that they graphically illustrate what else the individuals involved in the event could have done to prevent either the initiation or continuation of the event. HUMDEE trees also present the alternate paths available at the operator decision points in the incident/accident sequence. This is different from the Technique for Human Error Rate Prediction (THERP) event trees. There are many uses of these trees. They can be used for incident/accident investigations to show what other courses of actions were available and for training operators. The trees also have a consequence component so that not only the decision can be explored, also the consequence of that decision.

Ostrom, L.T.

1993-08-01

217

Semi-Supervised Learning with Trees  

Microsoft Academic Search

We describe a nonparametric Bayesian approach to generalizing from few labeled examples, guided by a larger set of unlabeled objects and the assumption of a latent tree-structure to the domain. The tree (or a distribution over trees) may be inferred using the unlabeled data. A prior over concepts generated by a mutation process on the inferred tree(s) allows efficient computation

Charles Kemp; Thomas L. Griffiths; Sean Stromsten; Joshua B. Tenenbaum

2003-01-01

218

CartograTree: connecting tree genomes, phenotypes and environment.  

PubMed

Today, researchers spend a tremendous amount of time gathering, formatting, filtering and visualizing data collected from disparate sources. Under the umbrella of forest tree biology, we seek to provide a platform and leverage modern technologies to connect biotic and abiotic data. Our goal is to provide an integrated web-based workspace that connects environmental, genomic and phenotypic data via geo-referenced coordinates. Here, we connect the genomic query web-based workspace, DiversiTree and a novel geographical interface called CartograTree to data housed on the TreeGenes database. To accomplish this goal, we implemented Simple Semantic Web Architecture and Protocol to enable the primary genomics database, TreeGenes, to communicate with semantic web services regardless of platform or back-end technologies. The novelty of CartograTree lies in the interactive workspace that allows for geographical visualization and engagement of high performance computing (HPC) resources. The application provides a unique tool set to facilitate research on the ecology, physiology and evolution of forest tree species. CartograTree can be accessed at: http://dendrome.ucdavis.edu/cartogratree. PMID:23433187

Vasquez-Gross, Hans A; Yu, John J; Figueroa, Ben; Gessler, Damian D G; Neale, David B; Wegrzyn, Jill L

2013-05-01

219

Do Invasive Trees have a Hydraulic Advantage over Native Trees?  

Microsoft Academic Search

The hypothesis was tested that invasive trees have hydraulic traits that contribute to their invasive nature. Five pairs of co-occurring invasive and native trees, in mesic habitats, were selected: (1) Tamarix ramosissima and Salix amygdaloides; (2) Robinia pseudoacacia and Alnus rhombifolia (3) Schinus terebinthifolius and Myrica cerifera; (4) Ligustrum sinense and Acer negundo; and (5) Sapium sebiferum and Diospyros virginiana,

R B Pratt; R A Black

2006-01-01

220

Relating phylogenetic trees to transmission trees of infectious disease outbreaks.  

PubMed

Transmission events are the fundamental building blocks of the dynamics of any infectious disease. Much about the epidemiology of a disease can be learned when these individual transmission events are known or can be estimated. Such estimations are difficult and generally feasible only when detailed epidemiological data are available. The genealogy estimated from genetic sequences of sampled pathogens is another rich source of information on transmission history. Optimal inference of transmission events calls for the combination of genetic data and epidemiological data into one joint analysis. A key difficulty is that the transmission tree, which describes the transmission events between infected hosts, differs from the phylogenetic tree, which describes the ancestral relationships between pathogens sampled from these hosts. The trees differ both in timing of the internal nodes and in topology. These differences become more pronounced when a higher fraction of infected hosts is sampled. We show how the phylogenetic tree of sampled pathogens is related to the transmission tree of an outbreak of an infectious disease, by the within-host dynamics of pathogens. We provide a statistical framework to infer key epidemiological and mutational parameters by simultaneously estimating the phylogenetic tree and the transmission tree. We test the approach using simulations and illustrate its use on an outbreak of foot-and-mouth disease. The approach unifies existing methods in the emerging field of phylodynamics with transmission tree reconstruction methods that are used in infectious disease epidemiology. PMID:24037268

Ypma, Rolf J F; van Ballegooijen, W Marijn; Wallinga, Jacco

2013-11-01

221

Two Trees: Migrating Fault Trees to Decision Trees for Real Time Fault Detection on International Space Station  

NASA Technical Reports Server (NTRS)

We started from ISS fault trees example to migrate to decision trees, presented a method to convert fault trees to decision trees. The method shows that the visualizations of root cause of fault are easier and the tree manipulating becomes more programmatic via available decision tree programs. The visualization of decision trees for the diagnostic shows a format of straight forward and easy understands. For ISS real time fault diagnostic, the status of the systems could be shown by mining the signals through the trees and see where it stops at. The other advantage to use decision trees is that the trees can learn the fault patterns and predict the future fault from the historic data. The learning is not only on the static data sets but also can be online, through accumulating the real time data sets, the decision trees can gain and store faults patterns in the trees and recognize them when they come.

Lee, Charles; Alena, Richard L.; Robinson, Peter

2004-01-01

222

Tree Hydraulics: How Sap Rises  

ERIC Educational Resources Information Center

Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

Denny, Mark

2012-01-01

223

Mixtures of (Constrained) Ultrametric Trees.  

ERIC Educational Resources Information Center

Presents a method for the estimation of ultrametric trees calibrated on subjects' pairwise proximity judgments of stimuli, capturing subject heterogeneity using a finite mixture formulation. An empirical example from published data shows the ability to deal with external constraints on the tree topology. (Author/SLD)

Wedel, Michel; DeSarbo, Wayne S.

1998-01-01

224

Genome Trees from Conservation Profiles  

PubMed Central

The concept of the genome tree depends on the potential evolutionary significance in the clustering of species according to similarities in the gene content of their genomes. In this respect, genome trees have often been identified with species trees. With the rapid expansion of genome sequence data it becomes of increasing importance to develop accurate methods for grasping global trends for the phylogenetic signals that mutually link the various genomes. We therefore derive here the methodological concept of genome trees based on protein conservation profiles in multiple species. The basic idea in this derivation is that the multi-component “presence-absence” protein conservation profiles permit tracking of common evolutionary histories of genes across multiple genomes. We show that a significant reduction in informational redundancy is achieved by considering only the subset of distinct conservation profiles. Beyond these basic ideas, we point out various pitfalls and limitations associated with the data handling, paving the way for further improvements. As an illustration for the methods, we analyze a genome tree based on the above principles, along with a series of other trees derived from the same data and based on pair-wise comparisons (ancestral duplication-conservation and shared orthologs). In all trees we observe a sharp discrimination between the three primary domains of life: Bacteria, Archaea, and Eukarya. The new genome tree, based on conservation profiles, displays a significant correspondence with classically recognized taxonomical groupings, along with a series of departures from such conventional clusterings.

Tekaia, Fredj; Yeramian, Edouard

2005-01-01

225

Electrical Treeing in Polymer Nanocomposites  

Microsoft Academic Search

This paper presents a study of electrical treeing phenomena in polymer nanocomposites. The polymer nanocomposite studied consists of epoxy resin as the base polymer and silica as the nano filler. Treeing experiments were conducted at a constant ac voltage of 20kV, 50Hz on epoxy samples without any fillers as well as epoxy silica nano composites with 1% by weight of

Sridhar Alapati; M. Joy Thomas

2008-01-01

226

Looking/Learning Drawing: Trees.  

ERIC Educational Resources Information Center

Secondary students are asked to study and compare three reproductions--Van Gogh's "Grove of Cypresses," Da Vinci's "Study of a Tree," and Mondrian's "Tree II." The activity will help students develop their powers of observation and analysis, powers that can be applied to their own drawings. (RM)

Hurwitz, Al; Blume, Sharon

1985-01-01

227

Orderly Spanning Trees with Applications  

Microsoft Academic Search

We introduce and study orderly spanning trees of plane graphs. This algorithmic tool generalizes canonical orderings, which exist only for triconnected plane graphs. Although not every plane graph admits an orderly spanning tree, we provide an algorithm to compute an orderly pair for any connected planar graph G, consisting of an embedded planar graph H isomorphic to G, and an

Yi-Ting Chiang; Ching-Chi Lin; Hsueh-I Lu

2001-01-01

228

Communism in trees goes underground  

NSDL National Science Digital Library

This news article reports that some trees give their neighbors carbon that they have captured from the atmosphere. Scientists discovered that shade enhances a tree's ability to receive and that carbon appears to travel via a subterranean web formed by a common group of fungi. The article concludes with references and sources (with contact information).

Strauss, E.; Online, Science N.

229

Constructing Trees for Region Description.  

National Technical Information Service (NTIS)

A thresholded (binary) image can be represented as a region tree in which each node corresponds to a component of 1's (object) or 0's (background). If regions O and B share a border, then one encloses the other. This enclosure relation defines the tree. T...

D. L. Milgram

1977-01-01

230

Tree preserving embedding  

PubMed Central

The goal of dimensionality reduction is to embed high-dimensional data in a low-dimensional space while preserving structure in the data relevant to exploratory data analysis such as clusters. However, existing dimensionality reduction methods often either fail to separate clusters due to the crowding problem or can only separate clusters at a single resolution. We develop a new approach to dimensionality reduction: tree preserving embedding. Our approach uses the topological notion of connectedness to separate clusters at all resolutions. We provide a formal guarantee of cluster separation for our approach that holds for finite samples. Our approach requires no parameters and can handle general types of data, making it easy to use in practice and suggesting new strategies for robust data visualization.

Shieh, Albert D.; Hashimoto, Tatsunori B.; Airoldi, Edoardo M.

2011-01-01

231

A Cost Benefit Analysis of Urban Trees  

SciTech Connect

Urban shade trees offer significant benefits in reducing building air- conditioning and improving urban air quality by reducing smog. The savings associated with these benefits varies by climate regions and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree planting programs can be designed offer savings to communities that plant trees.

Akbari, Hashem

1997-09-01

232

Terrestrial apes and phylogenetic trees  

PubMed Central

The image that best expresses Darwin’s thinking is the tree of life. However, Darwin’s human evolutionary tree lacked almost everything because only the Neanderthals were known at the time and they were considered one extreme expression of our own species. Darwin believed that the root of the human tree was very deep and in Africa. It was not until 1962 that the root was shown to be much more recent in time and definitively in Africa. On the other hand, some neo-Darwinians believed that our family tree was not a tree, because there were no branches, but, rather, a straight stem. The recent years have witnessed spectacular discoveries in Africa that take us close to the origin of the human tree and in Spain at Atapuerca that help us better understand the origin of the Neanderthals as well as our own species. The final form of the tree, and the number of branches, remains an object of passionate debate.

Arsuaga, Juan Luis

2010-01-01

233

Fault trees and sequence dependencies  

NASA Technical Reports Server (NTRS)

One of the frequently cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated by presenting several models of the fault-tolerant parallel processor, which include both hot and cold spares.

Dugan, Joanne Bechta; Boyd, Mark A.; Bavuso, Salvatore J.

1990-01-01

234

Tree-growth analyses to estimate tree species' drought tolerance.  

PubMed

Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very drought-tolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species. PMID:22363071

Eilmann, Britta; Rigling, Andreas

2012-02-01

235

Trees, networks and optimality  

NASA Astrophysics Data System (ADS)

Theoretical and observational material on form and function of natural networks appeared in somewhat disparate contexts from physics to biology is critically reviewed. Moving from the exact result that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, the properties and the dynamic origin of the scale-invariant structure of river patterns are discussed in relation to optimal selection. It is argued that at least in the fluvial landscape Nature works through imperfect searches for dynamically accessible optimal configurations and that purely random or deterministic constructs are clearly unsuitable to properly describe natural network forms. We also show that optimal networks are spanning loopless configurations only under precise physical requirements that arise under the constraints imposed by continuity. In the case of rivers, every spanning tree proves a local minimum of total energy dissipation. This is stated in a theorem form applicable to generic networks, suggesting that other branching structures occurring in nature (e.g., scale-free and looping) may possibly arise through optimality to different selective pressures. It is thus suggested that one recurrent self- organized mechanism for the dynamic origin of fractal forms is the robust strive for imperfect optimality that it is observed in many natural patterns, chief and foremost hydrologic ones.

Rinaldo, A.

2008-12-01

236

Reflecticons: Trees of a City.  

ERIC Educational Resources Information Center

Describes a four week artist-in-residence program called "Reflecticons: Trees of a City." Using handmade paper, the children of Kaukauna (Wisconsin) explored the heritage, development, and growth of their community from the 1700s to the present. (CMK)

Hoglund, Paula Stevenson

1999-01-01

237

Tree of Life Workshop Report  

NSF Publications Database

... Development meets Tree Of Life What are the most exciting questions in the Evolution of Development ... the key questions about the Evolution of Development? How does the community exploit these increased ...

238

Syntactic Structures as Multidimensional Trees  

Microsoft Academic Search

We survey a sequence of results relating model-theoretic and language-theoreticdefinability over an infinite hierarchy of multi-dimensional tree-like structures and explore their applications to a corresponding range of theoriesof syntax. We discuss, in particular, results for Government and Binding Theory(GB), Tree-Adjoining Grammar (TAG) and Generalized Phrase-Structure Grammar(GPSG) along with a generalized version of TAG extending TAG in much the sameway that

James Rogers

2003-01-01

239

On packing R-trees  

Microsoft Academic Search

We propose new R-tree packing techniques for static databases. Given a collection of rectangles, we sort them and build the R-tree bottom-up. There are several ways to sort the rectangles; the innovation of this work is the use of fractals, and specifically the hilbert curve, to achieve better ordering of the rectangles and eventually better pack- ing. We proposed and

Ibrahim Kamel; Christos Faloutsos

1993-01-01

240

Fault Tree Analysis: A Bibliography  

NASA Technical Reports Server (NTRS)

Fault tree analysis is a top-down approach to the identification of process hazards. It is as one of the best methods for systematically identifying an graphically displaying the many ways some things can go wrong. This bibliography references 266 documents in the NASA STI Database that contain the major concepts. fault tree analysis, risk an probability theory, in the basic index or major subject terms. An abstract is included with most citations, followed by the applicable subject terms.

2000-01-01

241

Water in the trunk of a tree  

NSDL National Science Digital Library

Every December, people cut down pine trees and other evergreens and stick them in their houses. The trees start sucking up water right away (unless you wait too long between cutting the tree and putting it in water, of course). A new study helps to explain how the heck water moves up the trunk of cone-making trees called "conifers."

American Association for the Advancement of Science (AAAS;)

2005-12-22

242

Modular approach to fault tree analysis  

Microsoft Academic Search

An analytical method to describe fault tree diagrams in terms of their modular composition is developed. Fault tree structures are characterized by recursively relating the top tree event to all its basic component inputs through a set of equations defining each of the modules for the fault tree. It is shown that such a modular description is an extremely valuable

J. Olmes; L. Wolf

1977-01-01

243

Sensitivity analysis of modular dynamic fault trees  

Microsoft Academic Search

Dynamic fault tree analysis, as currently supported by the Galileo software package, provides an effective means for assessing the reliability of embedded computer-based systems. Dynamic fault trees extend traditional fault trees by defining special gates to capture sequential and functional dependency characteristics. A modular approach to the solution of dynamic fault trees effectively applies Binary Decision Diagram (BOD) and Markov

Yong Ou; Joanne Bechta Dugan

2000-01-01

244

Locating Multiple Gene Duplications through Reconciled Trees  

Microsoft Academic Search

We introduce the first exact and efficient algorithm for Guig´ o et al.'s problem that, given a collection of rooted, binary gene trees and a rooted, binary species tree, determines a minimum number of locations for gene duplication events from the gene trees on the species tree. We examined the performance of our algorithm using a set of 85 gene

J. Gordon Burleigh; Mukul S. Bansal; André Wehe; Oliver Eulenstein

2008-01-01

245

Generic physical protection logic trees  

SciTech Connect

Generic physical protection logic trees, designed for application to nuclear facilities and materials, are presented together with a method of qualitative evaluation of the trees for design and analysis of physical protection systems. One or more defense zones are defined where adversaries interact with the physical protection system. Logic trees that are needed to describe the possible scenarios within a defense zone are selected. Elements of a postulated or existing physical protection system are tagged to the primary events of the logic tree. The likelihood of adversary success in overcoming these elements is evaluated on a binary, yes/no basis. The effect of these evaluations is propagated through the logic of each tree to determine whether the adversary is likely to accomplish the end event of the tree. The physical protection system must be highly likely to overcome the adversary before he accomplishes his objective. The evaluation must be conducted for all significant states of the site. Deficiencies uncovered become inputs to redesign and further analysis, closing the loop on the design/analysis cycle.

Paulus, W.K.

1981-10-01

246

If a Tree Falls in the Forest ...  

NSDL National Science Digital Library

This activity has students explore the role that forests play in their own lives by listing everyday products made from trees. They use the Internet to find as many uses for trees as possible in order to develop a class list that should include foods from trees, products derived from all parts of a tree, environmental benefits of trees, and recreational uses of trees. Students are then asked to imagine a day in their lives without trees and consider how their routine would differ and how their environment would change. This site also contains ideas for assessment and ways of extending the lesson.

247

Hi-trees and their layout.  

PubMed

We introduce hi-trees, a new visual representation for hierarchical data in which, depending on the kind of parent node, the child relationship is represented using either containment or links. We give a drawing convention for hi-trees based on the standard layered drawing convention for rooted trees, then show how to extend standard bottom-up tree layout algorithms to draw hi-trees in this convention. We also explore a number of other more compact layout styles for layout of larger hi-trees and give algorithms for computing these. Finally, we describe two applications of hi-trees: argument mapping and business decision support. PMID:21233514

Marriott, Kim; Sbarski, Peter; van Gelder, Tim; Prager, Daniel; Bulka, Andy

2011-03-01

248

Mechanisms of Resistance in Trees to Defoliators  

Microsoft Academic Search

At least 10 mechanisms are known to be important in resistance of trees to insect defoliators: 1) Phonological asynchrony\\u000a between host trees and insect herbivores; 2) Host tree tolerance of defoliation, which is linked to host tree vigor; 3) Host\\u000a tree compensatory photosynthesis and growth in response to defoliation; 4) Toughness of leaves and needles; 5) Low nutritive\\u000a quality of

Karen M. Clancy

249

On Straightening Low-Diameter Unit Trees  

Microsoft Academic Search

\\u000a A polygonal chain is a sequence of consecutively joined edges embedded in space. A k-chain is a chain of k edges. A polygonal tree is a set of edges joined into a tree structure embedded in space. A unit tree is a tree with only edges of unit length. A chain or a tree is simple if non-adjacent edges do

Sheung-hung Poon

2005-01-01

250

Ray tracing with the BSP tree  

Microsoft Academic Search

One of the most fundamental concepts in computer graphics is binary space subdivision. In its purest form, this concept leads to binary space partitioning trees (BSP trees) with arbitrarily oriented space partitioning planes. In practice, however, most algorithms use kd-trees-a special case of BSP trees that restrict themselves to axis-aligned planes-since BSP trees are believed to be numerically unstable, costly

Thiago Ize; Ingo Wald; S. G. Parker

2008-01-01

251

Sussing Merger Trees: The Merger Trees Comparison Project  

NASA Astrophysics Data System (ADS)

Merger trees follow the growth and merger of dark-matter haloes over cosmic history. As well as giving important insights into the growth of cosmic structure in their own right, they provide an essential backbone to semi-analytic models of galaxy formation. This paper is the first in a series to arise from the Sussing Merger Trees Workshop in which 10 different tree-building algorithms were applied to the same set of halo catalogues and their results compared. Although many of these codes were similar in nature, all algorithms produced distinct results. Our main conclusions are that a useful merger-tree code should possess the following features: (i) the use of particle IDs to match haloes between snapshots; (ii) the ability to skip at least one, and preferably more, snapshots in order to recover subhaloes that are temporarily lost during merging; (iii) the ability to cope with (and ideally smooth out) large, temporary fluctuations in halo mass. Finally, to enable different groups to communicate effectively, we defined a common terminology that we used when discussing merger trees and we encourage others to adopt the same language. We also specified a minimal output format to record the results.

Srisawat, Chaichalit; Knebe, Alexander; Pearce, Frazer R.; Schneider, Aurel; Thomas, Peter A.; Behroozi, Peter; Dolag, Klaus; Elahi, Pascal J.; Han, Jiaxin; Helly, John; Jing, Yipeng; Jung, Intae; Lee, Jaehyun; Mao, Yao-Yuan; Onions, Julian; Rodriguez-Gomez, Vicente; Tweed, Dylan; Yi, Sukyoung K.

2013-11-01

252

Genealogical trees from genetic distances  

NASA Astrophysics Data System (ADS)

In a population with haploid reproduction any individual has a single parent in the previous generation. If all genealogical distances among pairs of individuals (generations from the closest common ancestor) are known it is possible to exactly reconstruct their genealogical tree. Unfortunately, in most cases, genealogical distances are unknown and only genetic distances are available. The genetic distance between two individuals is measurable from differences in mtDNA (mitochondrial DNA) since in the case of humans or other complex organisms mtDNA is transmitted in a haploid manner. An analogous distance can be also computed for languages where it may be measured from lexical differences, in this case, nevertheless, haploid reproduction is only a raw approximation. Assuming a constant rate of mutation, these genetic distances are random and proportional only on average to genealogical ones. The reconstruction of the genealogical tree from the available genetic distances is forceful imprecise. In this paper we try to quantify the error one may commit in the reconstruction of the tree for different degrees of randomness. The errors may concern both topology of the tree (the branching hierarchy) and, in case of correct topology, the proportions of the tree (length of various branches).

Prignano, L.; Serva, M.

2009-06-01

253

Nitrogen nutrition of poplar trees.  

PubMed

Many forest ecosystems have evolved at sites with growth-limiting nitrogen (N) availability, low N input from external sources and high ecosystem internal cycling of N. By contrast, many poplar species are frequent constituents of floodplain forests where they are exposed to a significant ecosystem external supply of N, mainly nitrate, in the moving water table. Therefore, nitrate is much more important for N nutrition of these poplar species than for many other tree species. We summarise current knowledge of nitrate uptake and its regulation by tree internal signals, as well as acquisition of ammonium and organic N from the soil. Unlike herbaceous plants, N nutrition of trees is sustained by seasonal, tree internal cycling. Recent advances in the understanding of seasonal storage and mobilisation in poplar bark and regulation of these processes by temperature and daylength are addressed. To explore consequences of global climate change on N nutrition of poplar trees, responses of N uptake and metabolism to increased atmospheric CO(2) and O(3) concentrations, increased air and soil temperatures, drought and salt stress are highlighted. PMID:20398235

Rennenberg, H; Wildhagen, H; Ehlting, B

2010-03-01

254

Transport of Methane in Trees  

NASA Astrophysics Data System (ADS)

Although overall methane (CH4) emissions for croplands, wetlands, and forests have been measured, the exact dynamics of CH4 transport through trees is not well understood. What roles transport mechanisms play in emission rates has been thoroughly investigated for rice, but is fairly unknown for trees. Better defined plant transport mechanisms yield more accurate determination of greenhouse gas flux and its variations, contributing to a comprehensive theory quantifying greenhouse gas emissions globally. CH4 emissions from the common wetland tree species black cottonwood (Populus trichocarpa) native to the Pacific Northwest have been measured under hydroponic conditions in order to separate plant transport processes from the influence of soil processes. Canopy emissions of CH4 have been measured via canopy enclosure. Measurements of CH4 flux from each of 16 trees have indicated that emissions are normally constant over the half-hour sampling period. Samples for stable carbon isotope composition have been taken during these experiments and measured on a mass spectrometer. Compared to the isotopic composition of root water CH4, canopy CH4 is depleted in 13C; this indicates that CH4 moving through the tree is not following a bulk flow pathway (where no depletion would occur), but instead moves either diffusively or through other cell or tissue barriers. No correlation was found to exist between leaf area and CH4 emission; this is vital to upscaling tree-level emissions to the global scale since leaf area index (LAI) cannot be treated as an appropriate parameter to upscale flux. Correctly informing global-scale CH4 fluxes from plants requires an association between the role plant physiology plays in the production and transport of CH4 and magnitudes of flux. This research was supported by the Office of Science (BER), U. S. Department of Energy, Grant No. DE-FG02-08ER64515. Supported in part through NASA / Oregon Space Grant Consortium, grant NNG05GJ85H.

Kutschera, E.; Khalil, A. K.; Shearer, M. J.; Rosenstiel, T.; Rice, A. L.

2011-12-01

255

Trees, soils, and food security  

PubMed Central

Trees have a different impact on soil properties than annual crops, because of their longer residence time, larger biomass accumulation, and longer-lasting, more extensive root systems. In natural forests nutrients are efficiently cycled with very small inputs and outputs from the system. In most agricultural systems the opposite happens. Agroforestry encompasses the continuum between these extremes, and emerging hard data is showing that successful agroforestry systems increase nutrient inputs, enhance internal flows, decrease nutrient losses and provide environmental benefits: when the competition for growth resources between the tree and the crop component is well managed. The three main determinants for overcoming rural poverty in Africa are (i) reversing soil fertility depletion, (ii) intensifying and diversifying land use with high-value products, and (iii) providing an enabling policy environment for the smallholder farming sector. Agroforestry practices can improve food production in a sustainable way through their contribution to soil fertility replenishment. The use of organic inputs as a source of biologically-fixed nitrogen, together with deep nitrate that is captured by trees, plays a major role in nitrogen replenishment. The combination of commercial phosphorus fertilizers with available organic resources may be the key to increasing and sustaining phosphorus capital. High-value trees, 'Cinderella' species, can fit in specific niches on farms, thereby making the system ecologically stable and more rewarding economically, in addition to diversifying and increasing rural incomes and improving food security. In the most heavily populated areas of East Africa, where farm size is extremely small, the number of trees on farms is increasing as farmers seek to reduce labour demands, compatible with the drift of some members of the family into the towns to earn off-farm income. Contrary to the concept that population pressure promotes deforestation, there is evidence that demonstrates that there are conditions under which increasing tree planting is occurring on farms in the tropics through successful agroforestry as human population density increases.

Sanchez, P. A.; Buresh, R. J.; Leakey, R. R. B.

1997-01-01

256

Interpreting the universal phylogenetic tree.  

PubMed

The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist. PMID:10900003

Woese, C R

2000-07-18

257

Rhabdomyosarcoma of the biliary tree.  

PubMed

Rhabdomyosarcoma (RMS) of the biliary tree is a rare tumor in children that has a very poor prognosis. Preoperatively, it is often mistaken for a choledochal cyst. We report a case of RMS of the biliary tree in a 4-year-old girl who presented with abdominal pain and obstructive jaundice. The RMS was diagnosed at laparotomy; excision was not possible due to its size and localization. Chemotherapy achieved complete regression of the tumor observed at second-look surgery. Preoperative chemotherapy can now avoid mutilating surgical procedures and improve survival. PMID:9156861

Sanz, N; de Mingo, L; Flórez, F; Rollán, V

1997-02-01

258

Water Transport in Trees--An Artificial Laboratory Tree  

ERIC Educational Resources Information Center

Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

Susman, K.; Razpet, N.; Cepic, M.

2011-01-01

259

Tree Height Calculator: An Android App for Estimating Tree Height  

NASA Astrophysics Data System (ADS)

Conventionally, measuring tree height requires a collection of different tools - clinometer, transit, pencil, paper, laptop computer. Results are recorded manually and entered into a spreadsheet or database for future calculation and analysis. Tree Height Calculator is a mobile Android app the integrates the various steps in this process thereby improving the accuracy and dramatically reducing the time required to go from taking measurements to analyzing data. Given the user's height and the distance from the base of the tree (which can be downloaded into the app from a server), the app uses the phone's orientation sensor to calculate the angle of elevation. A simple trigonometric formula is then used to calculate and record the tree's height in the phone's database. When the phone has a WiFi connection, the data are transmitted to a server, from where they can be downloaded directly into a spreadsheet. The application was first tested in an Environmental Science laboratory at Trinity College. On the first trial, 103 data samples were collected, stored, and uploaded to the online database with only couple of dropped data points. On the second trial, 98 data samples were gathered with no loss of data. The app combined the individual measurements taken by the students in the lab, reducing the time required to produce a graph of the class's results from days to hours.

Burca, V. S.; Htet, N. M.; Huang, X.; de Lanerolle, T. R.; Morelli, R.; Gourley, J. R.

2011-12-01

260

Paint, lacquer, and varnish remover poisoning  

MedlinePLUS

Mirkin DB. Benzene and related aromatic hydrocarbons. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose . 4th ed. Philadelphia, Pa: ...

261

Alcohol CO-Production from Tree Crops.  

National Technical Information Service (NTIS)

A concept for the sustainable production of alcohol from fermentable substrates produced on an annual basis by the reproductive organs (pods, fruits, nuts, berries, etc.) of tree crops is presented. The advantages of tree-crop systems include suitability ...

M. Seibert G. Folger T. Milne

1982-01-01

262

Decision Trees for Prediction and Data Mining.  

National Technical Information Service (NTIS)

Three tree-structured algorithms are developed: GUIDE, CRUISE, and LOTUS. GUIDE is an algorithm for constructing least-squares, quantile, and Poisson regression trees. It can fit piecewise constant, piecewise polynomial, and piecewise multiple linear mode...

Y. Wei

2005-01-01

263

Generating Functions for Multi-labeled Trees.  

PubMed

Multi-labeled trees are a generalization of phylogenetic trees that are used, for example, in the study of gene versus species evolution and as the basis for phylogenetic network construction. Unlike phylogenetic trees, in a leaf-multi-labeled tree it is possible to label more than one leaf by the same element of the underlying label set. In this paper we derive formulae for generating functions of leaf-multi-labeled trees and use these to derive recursions for counting such trees. In particular, we prove results which generalize previous theorems by Harding on so-called tree-shapes, and by Otter on relating the number of rooted and unrooted phylogenetic trees. PMID:23175592

Czabarka, E; Erd?s, P L; Johnson, V; Moulton, V

2013-01-01

264

The Gift of the Tree  

NSDL National Science Digital Library

A piece of children's literature can be a powerful tool for teaching and learning science; however, it takes more than reading about a topic to qualify as "doing science." Inspired by the book, The Gift of the Tree , the author developed an in-dep

Jones, Marla W.

2009-09-01

265

Fault trees and imperfect coverage  

Microsoft Academic Search

A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault\\/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated

Joanne Bechta Dugan

1989-01-01

266

Trees of Our National Forests.  

ERIC Educational Resources Information Center

Presented is a description of the creation of the National Forests system, how trees grow, managing the National Forests, types of management systems, and managing for multiple use, including wildlife, water, recreation and other uses. Included are: (1) photographs; (2) line drawings of typical leaves, cones, flowers, and seeds; and (3)…

Forest Service (USDA), Washington, DC.

267

Multiway Iceberg Cubing on Trees  

Microsoft Academic Search

The Star-cubing algorithm performs multiway aggregation on trees but incurs huge memory consumption. We propose a new al- gorithm MG-cubing that achieves maximal multiway aggregation. Our experiments show that MG-cubing achieves similar and very often better time and memory efficiency than Star-cubing.

Pauline Lienhua Chou; Xiuzhen Zhang

2005-01-01

268

The Right Mix of Trees  

NSDL National Science Digital Library

This video describes the work of scientists who are studying the precise combination of trees that would be most effective in reducing the level of greenhouse gases in the air around Syracuse, NY. This is a pilot study that will serve as a model for other urban areas.

Forestry, New Y.; Suny-Esf, Syracuse

269

The Education of Little Tree.  

ERIC Educational Resources Information Center

First published in 1976, this autobiography contains Forrest Carter's--Little Tree's--remembrances of life with his Eastern Cherokee Hill country grandparents in the 1930s. There are 21 chapters, recounting humorous and serious episodes from a 5-year period and dealing with the themes of growing up, Indian life and values, family relationships,…

Carter, Forrest

270

Trees are Terrific...Travels with Pierre  

NSDL National Science Digital Library

This page, from the University of Illinois Extension, has an animated cartoon designed to help young children (5-8 years of age) gain an appreciation of trees, observe trees in their every day lives and develop an interest in learning more about trees. It is intended for adults to work with children to explore the wonders of trees. It meets several of the Illinois statewide learning goals for second grade. The teacher's guide includes a number of suggested activities.

271

Exploring the Secret Life of Trees  

NSDL National Science Digital Library

This page, from the University of Illinois Extension, has an animated cartoon designed to help 3rd through 5th grade students gain an appreciation of trees, observe trees in their everyday lives, and develop an interest in discovering more about trees. It is intended for adults to work with children to explore the secret life of trees. It meets several of the Illinois statewide learning goals for fourth grade. The teacher's guide suggests a number of supporting activities for students.

272

Wavelet tree quantization for copyright protection watermarking  

Microsoft Academic Search

This paper proposes a wavelet-tree-based blind watermarking scheme for copyright protection. The wavelet coefficients of the host image are grouped into so-called super trees. The watermark is embedded by quantizing super trees. The trees are so quantized that they exhibit a large enough statistical difference, which will later be used for watermark extraction. Each watermark bit is embedded in perceptually

Shih-hao Wang; Yuan-pei Lin

2004-01-01

273

Imaging Tree Roots with Borehole Radar  

Microsoft Academic Search

Ground-penetrating radar has been used to de- tect and map tree roots using surface-based antennas in reflection mode. On amenable soils these methods can accurately detect lateral tree roots. In some tree species (e.g. Pinus taeda, Pinus palustris), vertically orientated tap roots directly beneath the tree, comprise most of the root mass. It is difficult if not impossible to vertically

John R. Butnor; Kurt H. Johnsen; Per Wikström; Tomas Lundmark; Sune Linder

2006-01-01

274

Balancing minimum spanning and shortest path trees  

Microsoft Academic Search

This paper give a simple linear-time algorithm that, given a weighted\\u000adigraph, finds a spanning tree that simultaneously approximates a shortest-path\\u000atree and a minimum spanning tree. The algorithm provides a continuous\\u000atrade-off: given the two trees and epsilon > 0, the algorithm returns a\\u000aspanning tree in which the distance between any vertex and the root of the\\u000ashortest-path

Samir Khuller; Balaji Raghavacharit; Neal E. Young

1993-01-01

275

Tree Ring Data and Environmental Variables  

NSDL National Science Digital Library

This activity uses Bristlecone pine tree-ring data to understand how tree growth is related to environmental variables. It can be used to test hypotheses about how tree growth has been increasing with increasing northern hemisphere temperature in the past 100 years. This activity was originally developed by Christine Hallman and Katie Hirschboeck at the Laboratory of Tree-Ring Research at the University of Arizona. This activity is used in a Global Change course for first year non-science majors.

Bigio, Erica

276

Lookahead and Pathology in Decision Tree Induction  

Microsoft Academic Search

The standard approach to decision tree induction is a top-down, greedyalgorithm that makes locally optimal, irrevocable decisions at each nodeof a tree. In this paper, we study an alternative approach, in which thealgorithms use limited lookahead to decide what test to use at a node.We systematically compare, using a very large number of decision trees,the quality of decision trees induced

Sreerama K. Murthy; Steven Salzberg

1995-01-01

277

Isoprene emission from Indian trees  

NASA Astrophysics Data System (ADS)

Isoprene is the most dominant non-methane volatile organic compound (NMVOC) emitted by plants. NMVOCs play an important role in regulating the composition of atmospheric trace gases including global concentration of tropospheric ozone. Our present knowledge about NMVOCs emission is mainly from studies on temperate tree species. So far information on biogenic NMVOCs emission from tropical tree species is limited. In this study, isoprene emission rates from 40 tropical Indian tree species belonging to 33 genera and 17 families were measured for the first time using a dynamic flow through enclosure chamber technique. The isoprene emission rate from plants (30°C and PAR 1000 ?molm-2s-1) ranged from undetectable to 81.5 ?g g-1 h-1 and values were found to be comparable with other studies on tropical tree species. Tree species screened for isoprene emission in the present study may be grouped into the four categories, proposed by [2001], namely, 18 species were negligible or BDL isoprene emitting (<1 ?g g-1 h-1), 6 species were low emitting (1 ? to <10 ?g g-1 h-1), 5 species were moderate emitting (10? to <25 ?g g-1 h-1), and 11 species were high isoprene emitting (?25 ?g g-1 h-1). Maximum isoprene emission rate (81.5 ?g g-1 h-1) was observed in the case of Dalbergia sissoo Linn. It was interesting to find that Citrus limon Linn., Citrus reticulata Linn., Citrus sinensis Linn., Grevillea robusta A. Cunn., and Morus alba Linn., which were earlier reported as BDL or non isoprene emitters in US [, 1998; , 2001] were found to be appreciably high isoprene emitters (0.61-21.60 ?g g-1 h-1) in the present study.

Varshney, C. K.; Singh, Abhai Pratap

2003-12-01

278

Totally Tree-mendous Activities: Projects To Discover the Beauty and Benefits of Trees.  

ERIC Educational Resources Information Center

This teacher's guide supplies information and hands-on activities to teach about trees from several disciplines. Activities are grouped into six areas that cover botany, social studies, arts and literature (aesthetics), and trees as a resource. Sections include: (1) Tree Identification, which defines trees and leaves and presents activities that…

Hollister, Sarah

279

Combining dynamic fault trees and event trees for probabilistic risk assessment  

Microsoft Academic Search

As system analysis methodologies, both event tree analysis (ETA) and fault tree analysis (FTA) are used in probabilistic risk assessment (PRA), especially in identifying system interrelationships due to shared events. Although there are differences between them, ETA and FTA, are so closely linked that fault trees (FT) are often used to quantify system events that are part of event tree

Hong Xu; Joanne Bechta Dugan

2004-01-01

280

Ohio's Shade Tree Evaluation Project. In SEARCH OF A WELL ADAPTED TREE  

Microsoft Academic Search

Ohio's Shade Tree Evaluation Project is an attempt to evaluate trees for a different number of different characteristics. Similar projects are needed to determine those trees which are most suitable or more adaptable to particular locations. Projects of this nature serve not only the green industry, but also maintain a healthy urban tree population.

T Davis Sydnor

1984-01-01

281

Anisotropic branching random walks on homogeneous trees  

Microsoft Academic Search

Symmetric branching random walk on a homogeneous tree exhibits a weak sur- vival phase: For parameter values in a certain interval, the population survives forever with positive probability, but, with probability one, eventually vacates every finite subset of the tree. In this phase, particle trails must converge to the geometric boundaryof the tree. The random subset3 of the boundary consisting

I. Hueter; S. P. Lalley

1999-01-01

282

Anisotropic branching random walks on homogeneous trees  

Microsoft Academic Search

.   Symmetric branching random walk on a homogeneous tree exhibits a weak survival phase: For parameter values in a certain interval, the population survives forever with positive probability, but, with probability\\u000a one, eventually vacates every finite subset of the tree. In this phase, particle trails must converge to the geometric boundary? of the tree. The random subset ? of the

Irene Hueter; Steven P. Lalley

2000-01-01

283

On the topology of multicast trees  

Microsoft Academic Search

The benefit derived from using multicast is seemingly dependent upon the shape of the distribution tree. In this paper, we attempt to accurately model interdomain multicast trees. We measure a number of key parameters, such as depth, degree frequency, and average degree, for a number of real and synthetic data sets. We find that interdomain multicast trees actually do share

Robert C. Chalmers; Kevin C. Almeroth

2003-01-01

284

A construction of almost all Brauer trees  

Microsoft Academic Search

We know that almost all Brauer trees are shaped like a star. Given such a star and an odd prime l, we give an explicit method for constructing inflnitely many groups with this star as the Brauer tree of some l-block. Furthermore we show, that there is an inflnite family of Brauer trees which cannot be realized in the principal

Natalie Naehrig

2008-01-01

285

Foundations of Attack-Defense Trees  

NASA Astrophysics Data System (ADS)

We introduce and give formal definitions of attack-defense trees. We argue that these trees are a simple, yet powerful tool to analyze complex security and privacy problems. Our formalization is generic in the sense that it supports different semantical approaches. We present several semantics for attack-defense trees along with usage scenarios, and we show how to evaluate attributes.

Kordy, Barbara; Mauw, Sjouke; Radomirovi?, Saša; Schweitzer, Patrick

286

On multicast trees: structure and size estimation  

Microsoft Academic Search

This work presents a thorough investigation of the structure of multicast trees cut from the Internet and power-law topologies. Based on both generated topologies and real Internet data, we characterize the structure of such trees and show that they obey the rank-degree power law; that most high degree tree nodes are concentrated in a low diameter neighborhood; and that the

Danny Dolev; Osnat Mokryn; Yuval Shavitt

2006-01-01

287

Source-Tree Routing in Wireless Networks  

Microsoft Academic Search

We present the source-tree adaptive routing (STAR) protocol and analyze its performance in wireless networks with broadcast radio links. Routers in STAR communicate to its neighbors their source routing trees either incrementally or in atomic updates. Source routing trees are specified by stating the link parameters of each link belonging to the paths used to reach every destination. Hence, a

J. J. Garcia-luna-aceves; Marcelo Spohn

1999-01-01

288

TREES AND FOUNDATIONS—A REASSESSMENT  

Microsoft Academic Search

The abstraction of water from the soil by tree roots causes damage tofoundations by shrinking clay soils. The factors determining whether or not damage occurs are the water supply to the ground, the flow of water through the ground to the trees roots, the water demand of the tree, and the shrinkability of the clay. Crude investigation of the extent

Paul F. McCombie

1993-01-01

289

Diagnostic expert systems from dynamic fault trees  

Microsoft Academic Search

A methodology for developing a diagnostic map for systems that can be analyzed via a dynamic fault tree is proposed in this paper. This paper shows how to automatically design a diagnostic decision tree from a dynamic fault tree used for reliability analysis. In particular the methodology makes use of Markov chains since they are mathematical models used for reliability

Tariq Assaf; Joanne Bechta Dugan

2004-01-01

290

The Galileo Fault Tree Analysis Tool  

Microsoft Academic Search

We present Galileo, a dynamic fault tree modeling and analysis tool that combines the innovative DIF- Tree analysis methodology with a rich user interface built using package-oriented programming. DIFTree integrates binary decision diagram and Markov meth- ods under the common notation of dynamic fault trees, allowing the user to exploit the benefits of both tech- niques while avoiding the need

Kevin J. Sullivan; Joanne Bechta Dugan; David Coppit

1999-01-01

291

Formal methodology for fault tree construction  

Microsoft Academic Search

A model is presented for formulating the Boolean failure logic, cailed ; the fault tree, for electrical systems from associated schematic diagrams and ; system-independent component information. The model is developed in detail for ; electrical systems, while its implication and terminology extend to all fault ; tree construction. The methodology is verified as formal by fault trees ; constructed

Fussell

1973-01-01

292

Kinetic Medians and kd-Trees  

Microsoft Academic Search

We propose algorithms for maintaining two variants of -trees of a set of moving points in the plane. A pseudo -tree allows the number of points stored in the two children to differ by a constant factor. An overlapping -tree allows the bounding boxes of two children to overlap. We show that both of them support range search operations in

Pankaj K. Agarwal; Jie Gao; Leonidas J. Guibas

2002-01-01

293

Gene tree correction guided by orthology  

PubMed Central

Background Reconciled gene trees yield orthology and paralogy relationships between genes. This information may however contradict other information on orthology and paralogy provided by other footprints of evolution, such as conserved synteny. Results We explore a way to include external information on orthology in the process of gene tree construction. Given an initial gene tree and a set of orthology constraints on pairs of genes or on clades, we give polynomial-time algorithms for producing a modified gene tree satisfying the set of constraints, that is as close as possible to the original one according to the Robinson-Foulds distance. We assess the validity of the modifications we propose by computing the likelihood ratio between initial and modified trees according to sequence alignments on Ensembl trees, showing that often the two trees are statistically equivalent. Availability Software and data available upon request to the corresponding author.

2013-01-01

294

Hyperdominance in the Amazonian tree flora.  

PubMed

The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species--less diverse than the North American tree flora--accounts for half of the world's most diverse tree community. PMID:24136971

ter Steege, Hans; Pitman, Nigel C A; Sabatier, Daniel; Baraloto, Christopher; Salomão, Rafael P; Guevara, Juan Ernesto; Phillips, Oliver L; Castilho, Carolina V; Magnusson, William E; Molino, Jean-François; Monteagudo, Abel; Núñez Vargas, Percy; Montero, Juan Carlos; Feldpausch, Ted R; Coronado, Eurídice N Honorio; Killeen, Tim J; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Terborgh, John; Wittmann, Florian; Andrade, Ana; Laurance, William F; Laurance, Susan G W; Marimon, Beatriz S; Marimon, Ben-Hur; Guimarães Vieira, Ima Célia; Amaral, Iêda Leão; Brienen, Roel; Castellanos, Hernán; Cárdenas López, Dairon; Duivenvoorden, Joost F; Mogollón, Hugo F; Matos, Francisca Dionízia de Almeida; Dávila, Nállarett; García-Villacorta, Roosevelt; Stevenson Diaz, Pablo Roberto; Costa, Flávia; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Montoya, Alvaro Javier Duque; Fernandez Piedade, Maria Teresa; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Gribel, Rogerio; Fine, Paul V A; Peres, Carlos A; Toledo, Marisol; Aymard C, Gerardo A; Baker, Tim R; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Maas, Paul; Petronelli, Pascal; Stropp, Juliana; Zartman, Charles Eugene; Daly, Doug; Neill, David; Silveira, Marcos; Paredes, Marcos Ríos; Chave, Jerome; Lima Filho, Diógenes de Andrade; Jørgensen, Peter Møller; Fuentes, Alfredo; Schöngart, Jochen; Cornejo Valverde, Fernando; Di Fiore, Anthony; Jimenez, Eliana M; Peñuela Mora, Maria Cristina; Phillips, Juan Fernando; Rivas, Gonzalo; van Andel, Tinde R; von Hildebrand, Patricio; Hoffman, Bruce; Zent, Eglée L; Malhi, Yadvinder; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vos, Vincent; Zent, Stanford; Oliveira, Alexandre A; Schutz, Angela Cano; Gonzales, Therany; Trindade Nascimento, Marcelo; Ramirez-Angulo, Hirma; Sierra, Rodrigo; Tirado, Milton; Umaña Medina, María Natalia; van der Heijden, Geertje; Vela, César I A; Vilanova Torre, Emilio; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; Ferreira, Cid; Mesones, Italo; Torres-Lezama, Armando; Urrego Giraldo, Ligia Estela; Zagt, Roderick; Alexiades, Miguel N; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Palacios Cuenca, Walter; Pauletto, Daniela; Valderrama Sandoval, Elvis; Valenzuela Gamarra, Luis; Dexter, Kyle G; Feeley, Ken; Lopez-Gonzalez, Gabriela; Silman, Miles R

2013-10-18

295

Toxicology of Poison Oak (Rhus toxicodendron) and Poison Ivy (Rhus radicans) Extracts in the Rat.  

National Technical Information Service (NTIS)

The objective of the study was to determine the toxicity of extracts of poison ivy, poison oak, and a polyethylene glycol vehicle (Carbowax R) when given orally to rats. Throughout a seven-month study four groups of rats (N=15) were administered the follo...

C. W. Waller I. W. Waters

1974-01-01

296

Zinc Fertilization of Avocado Trees  

Microsoft Academic Search

Methods for Zn fertilization of 'Hass' avocado (Persea americana Mill.) trees were evaluated in a 2-year field experiment on a commercial orchard located on a calcareous soil (pH 7.8) in Ventura County, Calif. The fertilization methods included soil- or irrigation-applied ZnSO4; irrigation-applied Zn chelate (Zn- EDTA); trunk injection of Zn(NO3)2, and foliar applications of ZnSO4, ZnO, or Zn metalosate. Other

David E. Crowley; Woody Smith

297

Organic & Integrated Tree Fruit Production  

NSDL National Science Digital Library

Part of the Washington State University Tree Fruit Research and Extension Center, this website offers various resources for orchardists interested in organic and integrated production methods. The site contains sections on Organic Fruit Production, Soil and Pest Management, Apple Replant Disease, and more. The site also offers links to other Washington State University sites for Horticulture, Entomology, Fruit Pathology, and Postharvest resources. Many of the documents on this site are available for download as PDF files.

2007-08-02

298

Foreign body in tracheobronchial tree  

Microsoft Academic Search

Foreign body inhalation into the tracheobronchial tree can prove to be a life threatening unless timely intervened and appropriate\\u000a steps are being taken towards its management [1]. A review of 32 cases was done at MP Shah Medical College Jamnagar over a\\u000a period of 2 years. Children were most susceptible to aspiration of foreign bodies. All the cases were selected

Vikas Sinha; Viral Chhaya; Dilavar S. Barot; Keyur Mehta; Parin Patel; Swapna Patil; Vishal Parmar; C. D. Pashanth; Niral Modi; Rahul Patel

2010-01-01

299

Cover trees for nearest neighbor  

Microsoft Academic Search

Abstract We present a tree data structure for fast nearest neighbor operations in general n- point metric spaces (where the data set con- sists of n points). The data structure re- quires O(n) space regardless of the met- ric’s structure yet maintains all performance properties of a navigating net [KL04a]. If the point set has a bounded expansion con- stant

Alina Beygelzimer; Sham Kakade; John Langford

2006-01-01

300

Tree climbing and human evolution  

PubMed Central

Paleoanthropologists have long argued—often contentiously—about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter–gatherers use extraordinary ankle dorsiflexion (>45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion in museum specimens of climbing hunter–gatherers from the Ituri forest, we did find that climbing by the Twa is associated with longer fibers in the gastrocnemius muscle relative to those of neighboring, nonclimbing agriculturalists. This result suggests that a more excursive calf muscle facilitates climbing with a bipedally adapted ankle and foot by positioning the climber closer to the tree, and it might be among the mechanisms that allow hunter–gatherers to access the canopy safely. Given that we did not find a skeletal correlate for this observed behavior, our results imply that derived aspects of the hominin ankle associated with bipedalism remain compatible with vertical climbing and arboreal resource acquisition. Our findings challenge the persistent arboreal–terrestrial dichotomy that has informed behavioral reconstructions of fossil hominins and highlight the value of using modern humans as models for inferring the limits of hominin arboreality.

Venkataraman, Vivek V.; Kraft, Thomas S.; Dominy, Nathaniel J.

2013-01-01

301

Dendrochemistry: Seeing the forest through the trees  

NASA Astrophysics Data System (ADS)

Dendrochemistry is a term used to describe the compositional analysis of tree-rings and its application to biomonitoring of the tree's environment. The central hypothesis of this study is that the concentrations of silver and gold in tree-rings in the Mediterranean region record the history of African dust storms. Although there have been previous studies of tree-ring composition using both NAA and other analytical techniques, to the author's knowledge, this is the first dendrochemical study to consider the effects of dust storms on tree-ring chemistry. However, the results, as with many other dendrochemical studies, are promising at best. The tree-ring concentrations in a single tree in west-central Turkey were highly correlated with the local aerosol index obtained from the Total Ozone Mapping Spectrometer (TOMS). This suggests that silver and gold concentrations in carefully selected trees may serve as a proxy indicator of dust storm activity and indirectly, the phase of the North Atlantic Oscillation. Three other trees from the same forest did not have any silver or gold concentration peaks and possible reasons for this discrepancy are discussed. The correlation with dust storms is still uncertain because it was impossible to gather appropriate information about soil characteristics or additional trees for sampling to prove or disprove the hypothesis. However, the chemistries of silver and gold are discussed to elucidate why they may be uniquely good at recording environmental signals in tree-rings. Some promising results for detecting volcanic eruptions in tree-rings were obtained on tree samples of a shorter duration (20-30 years) from Catacik Turkey that were prepared for irradiation under improved conditions of cleanliness. These tree samples were analyzed later in the project after sample preparation procedures were altered to reduce the possibility of sample contamination. Concentration peaks in the Catacik samples were correlated with the timing of the Pinatubo eruption (1991) and the El Chichon eruption in 1982. However, many of the concentration peaks were in single trees and could not be verified by comparison to other trees that grew nearby. The relative success of correlating concentration peaks in these shorter tree sequences may have been due to the improved sample preparation procedures. Another possible explanation is that concentration peaks do not remain in the tree-rings over time due to diffusion or mobilization by the tree. This would make it more difficult to find or identify possible environmental signals in the older rings of a long tree sequence. Unfortunately, this study contributes to the overwhelming number of feasibility studies that have been performed since the 1950s. There is still no consensus regarding the mechanisms responsible for recording environmental events in tree-rings beyond passive uptake. The feasibility of dendrochemistry will be more firmly established by moving forward with thoughtfully planned control studies. The refined NAA procedures developed here are necessary for future experiments which should strive to understand the actual mechanisms responsible for uptake. There are several different aspects of dendrochemistry that could be tested with control studies and that would be useful for interpreting tree-ring chemistry. For instance, dendrochemical studies could focus on the variation in specific elements between trees and the creation of composite forest chronologies for the appropriate elements. If this was successful, it would indicate that tree-ring compositions faithfully record environmental conditions in some cases and for some elements. A possible correlation was found between the Ag and Au concentration in tree-rings and the intensity and frequency of dust storms. However, the promising results were only found for one tree out of four sampled in the Catacik forest. A future study could be dedicated to verifying the presence of the Ag and Au signals in other trees in the same forest. Future studies could also analyze the ground water near sample sites to mon

Hauck, Danielle K.

302

Enumerating All Rooted Trees Including k Leaves  

NASA Astrophysics Data System (ADS)

This paper presents an efficient algorithm to generate all (unordered) rooted trees with exactly n vertices including exactly k leaves. There are known results on efficient enumerations of some classes of graphs embedded on a plane, for instance, biconnected and triconnected triangulations [3], [6], and floorplans [4]. On the other hand, it is difficult to enumerate a class of graphs without a fixed embedding. The paper is on enumeration of rooted trees without a fixed embedding. We already proposed an algorithm to generate all “ordered” trees with n vertices including k leaves [11], while the algorithm cannot seem to efficiently generate all (unordered) rooted trees with n vertices including k leaves. We design a simple tree structure among such trees, then by traversing the tree structure we generate all such trees in constant time per tree in the worst case. By repeatedly applying the algorithm for each k=1,2,...,n-1, we can also generate all rooted trees with exactly n vertices.

Ishikawa, Masanobu; Yamanaka, Katsuhisa; Otachi, Yota; Nakano, Shin-Ichi

303

Assessment of student conceptions of evolutionary trees  

NASA Astrophysics Data System (ADS)

Biologists use evolutionary trees to depict hypotheses about the relationships among taxa. Trees possess lines that represent lineages, internal nodes that represent where lineages become evolutionarily isolated from one another and terminal nodes that represent the taxa under consideration. Interpreting a tree (i.e., "tree-thinking") is an important skill for biologists yet many students struggle when reading evolutionary trees. Common documented misconceptions include using morphological similarity, internal node counting or terminal node proximity, instead of identifying the internal node that represents a most recent common ancestor (MRCA), to determine relationships among taxa. I developed an instrument to assess whether students were using common ancestry or another, non-scientific, strategy to determine relationships among taxa. The study is the first to explicitly test hypotheses about how students approach reading evolutionary trees. To test the hypotheses an instrument was developed. The instrument is the first reliable and valid assessment testing student understanding of how to use most recent common ancestor to interpret evolutionary relationships in tree diagrams. Instructors can use the instrument as a diagnostic tool enabling them to help students learn this challenging concept. This study shows that, contrary to the assertion that students hold misconceptions about evolutionary trees made in the literature, students do not consistently use erroneous strategies when interpreting trees. This study suggests that a constructivist perspective of cognitive structure describes students' conception of evolutionary trees more closely than a misconception perspective.

Blacquiere, Luke

304

Self-Organizing Tree Using Cluster Validity  

NASA Astrophysics Data System (ADS)

Self-organizing tree (S-TREE) models solve clustering problems by imposing tree-structured constraints on the solution. It has a self-organizing capacity and has better performance than previous tree-structured algorithms. S-TREE carries out pruning to reduce the effect of bad leaf nodes when the tree reaches a predetermined maximum size (U), However, it is difficult to determine U beforehand because it is problem-dependent. U gives the limit of tree growth and can also prevent self-organization of the tree. It may produce an unnatural clustering. In this paper, we propose an algorithm for pruning algorithm that does not require U. This algorithm prunes extra nodes based on a significant level of cluster validity and allows the S-TREE to grow by a self-organization. The performance of the new algorithm was examined by experiments on vector quantization. The results of experiments show that natural leaf nodes are formed by this algorithm without setting the limit for the growth of the S-TREE.

Sasaki, Yasue; Suzuki, Yukinori; Miyamoto, Takayuki; Maeda, Junji

305

Computing the joint distribution of tree shape and tree distance for gene tree inference and recombination detection.  

PubMed

Ancestral recombination events can cause the underlying genealogy of a site to vary along the genome. We consider Bayesian models to simultaneously detect recombination breakpoints in very long sequence alignments and estimate the phylogenetic tree of each block between breakpoints. The models we consider use a dissimilarity measure between trees in their prior distribution to favor similar trees at neighboring loci. We show empirical evidence in Enterobacteria that neighboring genomic regions have similar trees. The main hurdle in using such models is the need to properly calculate the normalizing function for the prior probabilities on trees. In this work, we quantify the impact of approximating this normalizing function as done in biomc2, a hierarchical Bayesian method to detect recombination based on distance between tree topologies. We then derive an algorithm to calculate the normalizing function exactly, for a Gibbs distribution based on the Robinson-Foulds (RF) distance between gene trees at neighboring loci. At the core is the calculation of the joint distribution of the shape of a random tree and its RF distance to a fixed tree. We also propose fast approximations to the normalizing function, which are shown to be very accurate with little impact on the Bayesian inference. PMID:24384712

Chung, Yujin; Perna, Nicole T; Ané, Cécile

2013-01-01

306

TreeNetViz: revealing patterns of networks over tree structures.  

PubMed

Network data often contain important attributes from various dimensions such as social affiliations and areas of expertise in a social network. If such attributes exhibit a tree structure, visualizing a compound graph consisting of tree and network structures becomes complicated. How to visually reveal patterns of a network over a tree has not been fully studied. In this paper, we propose a compound graph model, TreeNet, to support visualization and analysis of a network at multiple levels of aggregation over a tree. We also present a visualization design, TreeNetViz, to offer the multiscale and cross-scale exploration and interaction of a TreeNet graph. TreeNetViz uses a Radial, Space-Filling (RSF) visualization to represent the tree structure, a circle layout with novel optimization to show aggregated networks derived from TreeNet, and an edge bundling technique to reduce visual complexity. Our circular layout algorithm reduces both total edge-crossings and edge length and also considers hierarchical structure constraints and edge weight in a TreeNet graph. These experiments illustrate that the algorithm can reduce visual cluttering in TreeNet graphs. Our case study also shows that TreeNetViz has the potential to support the analysis of a compound graph by revealing multiscale and cross-scale network patterns. PMID:22034366

Gou, Liang; Zhang, Xiaolong Luke

2011-12-01

307

Electrical tree in ethylene based copolymers  

Microsoft Academic Search

The electrical treeing resistance of ethylene-based copolymers is investigated. It is shown that the AC tree initiation voltages of copolymers with small contents (<5~7 wt.%) of polar monomers are higher than that of LDPE (low-density polyethylene). Removal of free oxygen gas by vacuum degassing treatment makes tree initiation voltage 6-7 times higher in LDPE and styrene-graft polyethylene. In EVA (ethylene-vinylacetate)

N. Shimizu; H. Asai; H. Ishihara; K. Uchida; S. Rasikawan

1992-01-01

308

On the ideals of equivariant tree models  

Microsoft Academic Search

We introduce equivariant tree models in algebraic statistics, which unify and generalise existing tree models such as the\\u000a general Markov model, the strand symmetric model, and group-based models such as the Jukes–Cantor and Kimura models. We focus\\u000a on the ideals of such models. We show how the ideals for general trees can be determined from the ideals for stars. A

Jan Draisma; Jochen Kuttler

2009-01-01

309

Signs of Change: Studying Tree Rings  

NSDL National Science Digital Library

In this very hands-on lesson, students will learn about dendrochronology (the study of tree rings to answer ecological questions about the recent past) and come up with conclusions as to what possible climatic conditions might affect tree growth in their region. Students determine the average age of the trees in their schoolyard, investigate any years of poor growth, and draw conclusions about the reasons for the years of poor growth.

2007-01-01

310

Efficient Spectrum Sensing With Dyadic Tree Partitioning  

Microsoft Academic Search

A low-complexity spectrum-sensing method that is based on dyadic (binary) tree partitioning is proposed. For this purpose, first, a representation of the spectrum occupation with a dyadic tree is developed. Then, the accuracy of this representation is evaluated through a rate-distortion criterion. Using this criterion, a pruning algorithm for the dyadic tree that minimizes the number of sensing operations for

Lionel Gueguen; Berna Sayrac

2010-01-01

311

Tutorial: Advanced fault tree applications using HARP  

NASA Technical Reports Server (NTRS)

Reliability analysis of fault tolerant computer systems for critical applications is complicated by several factors. These modeling difficulties are discussed and dynamic fault tree modeling techniques for handling them are described and demonstrated. Several advanced fault tolerant computer systems are described, and fault tree models for their analysis are presented. HARP (Hybrid Automated Reliability Predictor) is a software package developed at Duke University and NASA Langley Research Center that is capable of solving the fault tree models presented.

Dugan, Joanne Bechta; Bavuso, Salvatore J.; Boyd, Mark A.

1993-01-01

312

Tree initiation phenomena in nanostructured epoxy composites  

Microsoft Academic Search

Tree initiation time was evaluated by a pulse detection system to detect a small PD (partial discharge) signal that might take place at first just after a tree was formed. Six kinds of materials were prepared for evaluation, i.e. base epoxy resin, microcomposite, two kinds of nanocomposites, and two kinds of nano-micro-mixed-composites. Lengths of trees detected were around 100 ?m

Yu Chen; Takahiro Imai; Yoshimichi Ohki; Toshikatsu Tanaka

2010-01-01

313

Teaching Through Trade Books: Talking Trees  

NSDL National Science Digital Library

Students love outdoor activities and will love them even more when they build confidence in their tree identification and measurement skills. The activities in this month's Teaching Through Trade Books column help students learn to identify the major characteristics of trees and discover how the pace--a nonstandard measuring unit--can be used to estimate not only distances but also the height of a tree.

Tolman, Marvin

2005-02-01

314

Immunological Analysis of Allergenic Tree Nut Proteins  

Microsoft Academic Search

Allergies are a growing problem in industrialized countries, with food allergies affecting 6% of children and 3-4% of adults. Tree nuts are a common cause of food-induced allergy and include walnut, cashew, almond, hazelnut, pistachio, pecan, chestnut, and Brazil nut. Tree nut allergy, in particular, affects 0.5% of the US population. Unlike other food allergies, tree nut allergy persists throughout

LeAnna N. Willison

2009-01-01

315

SAH KD-tree construction on GPU  

Microsoft Academic Search

KD-tree is one of the most efficient acceleration data structures for ray tracing. In this paper, we present a kd-tree construction algorithm that is precisely SAH-optimized and runs entirely on GPU. We construct the tree nodes in breadth-first order. In order to precisely evaluate the SAH cost, we design a parallel scheme based on the standard parallel scan primitive to

Zhefeng Wu; Fukai Zhao; Xinguo Liu

2011-01-01

316

Horizontal subsea trees allow frequent deepwater workovers  

SciTech Connect

Horizontal subsea wellheads have found application in the Liuhua oil field in the South China Sea. These trees allow installation and retrieval of downhole equipment through the tree without having to disturb the tree or its external connections to flow lines, service lines, or control umbilicals. This access to the well is important because the Liuhua wells will be produced with electrical submersible pumps (ESPs), which may have relatively short intervals between maintenance, leading to frequent well work. The wells will be completed subsea in about 300 m of water. The large bore, horizontal trees allow all downhole equipment to be pulled without removal of the subsea tree. This wellhead configuration also provides well control and vertical access to downhole equipment through a conventional marine drilling riser and subsea blowout preventer (BOP), eliminating the need for costly specialized completion risers. Another benefit of the horizontal tree is its extremely compact profile with a low number of valves for well control. Valve size and spacing are decoupled from the size and bore spacing of the tubing hanger. The tree`s low profile geometry reduces costs of manufacturing the tree and framework and optimize load transfer to the wellhead.

Krenek, M. [FMC Wellhead Equipment Division, Houston, TX (United States); Hall, G. [Amoco Corp., Shekou (China); Sheng, W.Z. [China Offshore Nanhai East Corp., Shekou (China)

1995-05-01

317

Tree ring record chronicles major Mesoamerican droughts  

NASA Astrophysics Data System (ADS)

A new tree ring record chronicles major Mesoamerican droughts in the past millennium that may have contributed to the decline of some pre-Hispanic civilizations. Although there is other evidence of droughts during the past millennium, the paleoclimate record had gaps. Stahle et al. used core samples from Montezuma bald cypress trees found in Barranca de Amealco, Querétaro, Mexico, to develop a 1238-year tree ring chronology. They reconstructed the soil moisture record from the tree ring growth patterns. The new record provides the first dated, annually resolved climate record for Mexico and Central America spanning this time period.(Geophysical Research Letters, doi:10.1029/2010GL046472, 2011)

Tretkoff, Ernie

2011-05-01

318

Minimax Trees in Linear Time with Applications  

NASA Astrophysics Data System (ADS)

A minimax tree is similar to a Huffman tree except that, instead of minimizing the weighted average of the leaves' depths, it minimizes the maximum of any leaf's weight plus its depth. Golumbic (1976) introduced minimax trees and gave a Huffman-like, {O}{n log n}-time algorithm for building them. Drmota and Szpankowski (2002) gave another {O}{n log n}-time algorithm, which takes linear time when the weights are already sorted by their fractional parts. In this paper we give the first linear-time algorithm for building minimax trees for unsorted real weights.

Gawrychowski, Pawe?; Gagie, Travis

319

Tree models for macroevolution and phylogenetic analysis.  

PubMed

It has long been recognized that phylogenetic trees are more unbalanced than those generated by a Yule process. Recently, the degree of this imbalance has been quantified using the large set of phylogenetic trees available in the TreeBASE data set. In this article, a more precise analysis of imbalance is undertaken. Trees simulated under a range of models are compared with trees from TreeBASE and two smaller data sets. Several simple models can match the amount of imbalance measured in real data. Most of them also match the variance of imbalance among empirical trees to a remarkable degree. Statistics are developed to measure balance and to distinguish between trees with the same overall imbalance. The match between models and data for these statistics is investigated. In particular, age-dependent (Bellman-Harris) branching process are studied in detail. It remains difficult to separate the process of macroevolution from biases introduced by sampling. The lessons for phylogenetic analysis are clearer. In particular, the use of the usual proportional to distinguishable arrangements (uniform) prior on tree topologies in Bayesian phylogenetic analysis is not recommended. PMID:21865338

Jones, Graham R

2011-12-01

320

Tree-space statistics and approximations for large-scale analysis of anatomical trees.  

PubMed

Statistical analysis of anatomical trees is hard to perform due to differences in the topological structure of the trees. In this paper we define statistical properties of leaf-labeled anatomical trees with geometric edge attributes by considering the anatomical trees as points in the geometric space of leaf-labeled trees. This tree-space is a geodesic metric space where any two trees are connected by a unique shortest path, which corresponds to a tree deformation. However, tree-space is not a manifold, and the usual strategy of performing statistical analysis in a tangent space and projecting onto tree-space is not available. Using tree-space and its shortest paths, a variety of statistical properties, such as mean, principal component, hypothesis testing and linear discriminant analysis can be defined. For some of these properties it is still an open problem how to compute them; others (like the mean) can be computed, but efficient alternatives are helpful in speeding up algorithms that use means iteratively, like hypothesis testing. In this paper, we take advantage of a very large dataset (N = 8016) to obtain computable approximations, under the assumption that the data trees parametrize the relevant parts of tree-space well. Using the developed approximate statistics, we illustrate how the structure and geometry of airway trees vary across a population and show that airway trees with Chronic Obstructive Pulmonary Disease come from a different distribution in tree-space than healthy ones. Software is available from http://image.diku.dk/aasa/software.php. PMID:24683959

Feragen, Aasa; Owen, Megan; Petersen, Jens; Wille, Mathilde M W; Thomsen, Laura H; Dirksen, Asger; de Bruijne, Marleen

2013-01-01

321

Methodology for system analysis using fault trees, success trees, and importance evaluations  

Microsoft Academic Search

This dissertation describes an investigation of certain methods available for reactor safety analyses. These approaches include fault-tree and success-tree approaches. It then focuses on the application, development, and evaluation of several importance measures for use with fault-tree and success-tree analyses. These developments provide a basis on which to develop a thorough and systematic approach to sensitivity analysis when using fault

Sharirli

1985-01-01

322

Analysis of KDT-Trees: KD-Trees Improved by Local Reogranisations  

Microsoft Academic Search

This paper deals with kd-tree like structures that implement the multidimensional dictionary. It presents the first efficient online reorganisation method that improves the performance of kd-trees. We propose a new variation of kd-trees, to be called kdt-trees, whereby the updating procedures guarantee that any subtree of size greater than 2t, t0, has at least t nodes on each side. Thus,

Walter Cunto; Gustavo Lau; Philippe Flajolet

1989-01-01

323

Sulfur nutrition of deciduous trees  

NASA Astrophysics Data System (ADS)

Sulfur in its reduced form (-II) is an essential nutrient for growth and development, but is mainly available to plants in its oxidised form as sulfate. Deciduous trees take up sulfate by the roots from the soil solution and reduce sulfate to sulfide via assimilatory sulfate reduction in both roots and leaves. For reduction in the leaves, sulfate is loaded into the xylem and transported to the shoot. The surplus of sulfate not reduced in the chloroplast or stored in the vacuole and the surplus of reduced S not used for protein synthesis in the leaves is loaded into the phloem and transported back to the roots. Along the transport path, sulfate and glutathione (GSH) is unloaded from the phloem for storage in xylem and phloem parenchyma as well as in pit and ray cells. Re-mobilised S from storage tissues is loaded into the xylem during spring, but a phloem to xylem exchange does not appear to exist later in the season. As a consequence, a cycling pool of S was only found during the change of the seasons. The sulfate:glutathione ratio in the phloem seems to be involved in the regulation of S nutrition. This picture of S nutrition is discussed in relation to the different growth patterns of deciduous trees from the temperate climate zone, i.e. (1) terminated, (2) periodic and (3) indeterminate growth patterns, and in relation to environmental changes.

Herschbach, Cornelia; Rennenberg, Heinz

2001-01-01

324

Identifying species of individual trees using airborne laser scanner  

Microsoft Academic Search

Individual trees can be detected using high-density airborne laser scanner data. Also, variables characterizing the detected trees such as tree height, crown area, and crown base height can be measured. The Scandinavian boreal forest mainly consists of Norway spruce (Picea abies L. Karst.), Scots pine (Pinus sylvestris L.), and deciduous trees. It is possible to separate coniferous from deciduous trees

Johan Holmgren; Åsa Persson

2004-01-01

325

On the Use of Context Tree for Binary Image Compression  

Microsoft Academic Search

We consider the use of a static context tree for binary image compression. The contexts are stored in the leaves of a variable-depth binary tree. The tree structure itself is fully static and optimized off-line for a training image. The structure of the tree is similar for different images of the same type. The benefit from optimizing the tree for

Pasi Friinti; Eugene I. Ageenko

1999-01-01

326

Disk Tree: A Fat-Tree Based Heterogeneous Multi-tier Storage Architecture  

Microsoft Academic Search

Traditional disk arrays have the internal bus bottleneck and can not scale well. This paper proposes Disk Tree, a novel Fat-tree based heterogeneous multi-tier storage architecture. Disk Tree is built from a collection of storage nodes, small storage appliances containing commodity disks, CPU, RAM and interconnection interfaces. Each node provides moderate levels of reliability, availability, and performance. We examine four

Zhikun Wang; Ke Zhou; Dan Feng; Junping Liu

2007-01-01

327

GIS in management of landscape trees: Determining, monitoring and implementing safety measures on potentially hazardous trees  

Microsoft Academic Search

Trees located in the vicinity public areas such as roadsides, recreation areas, and around building should be monitored regularly for structural weakness. Certain conditions can cause a tree to be structurally weakened so that parts or all of it are likely to collapse Landscape trees do not only contribute to the enhancement of scenery but might also become potential hazards

Masbiha Mat Isa; Noriah Othman; Rosmadi Ghazali

2012-01-01

328

Whole-tree water transport scales with sapwood capacitance in tropical forest canopy trees  

Microsoft Academic Search

The present study examines the manner in which several whole-tree water transport properties scale with species- specific variation in sapwood water storage capacity. The hypothesis that constraints on relationships between sap- wood capacitance and other water relations characteristics lead to predictable scaling relationships between intrinsic capacitance and whole-tree behaviour was investigated. Samples of sapwood from four tropical forest canopy tree

F. C. MEINZER; S. A. JAMES; G. GOLDSTEIN; D. WOODRUFF

2003-01-01

329

Balanced aspect ratio trees: combining the advantages of k -d trees and octrees  

Microsoft Academic Search

Given a set S of n points in lRd, we show, for fixed d, how to construct in O(n log n) time a data structure we call the Balanced Aspect Ratio (BAR) tree. A BAR tree is a binary space partition tree on S that has O(logn) depth and in which every region is convex and \\

Christian A. Duncan; Michael T. Goodrich; Stephen G. Kobourov

1999-01-01

330

Balanced Aspect Ratio Trees: Combining the Advantages of k-d Trees and Octrees  

Microsoft Academic Search

Given a set S of n points on Rd, we show, for fixed d, how to construct in O(nlogn) time a data structure we call the balanced aspect ratio (BAR) tree. A BAR tree is a binary space partition tree on S that has O(logn) depth in which every region is convex and “fat” (that is, has a bounded aspect

Christian A. Duncan; Michael T. Goodrich; Stephen G. Kobourov

2001-01-01

331

Comparative Use of Tree Leaves, Needles, Tree Barks and Lichens for Air Pollution Biomonitoring  

Microsoft Academic Search

The aim of this work is to determine the most suitable bioaccumulators for air pollution survey in Morocco. For this, we compare in this paper heavy metals uptake efficiencies for different types of biomonitors: leaves of oak and eucalyptus trees, needles of coniferous trees, tree-barks and lichens collected at the same site. Instrumental neutron activation analysis using the k0 method

T. El Khoukhi; R. Cherkaoui El Moursli; A. Chouak; Z. Moutia; M. Lferde; A. Senhou; A. Gaudry; S. Ayrault; M. Chakir

2005-01-01

332

Alkaline transition of phytocyanins: a comparison of stellacyanin and umecyanin.  

PubMed Central

The effect of pH on Cu(I) and Cu(II) forms of the isolated soluble domain of the stellacyanin from Rhus vernicifera (SCu), the Japanese lacquer tree, has been studied by electronic and NMR spectroscopy and using direct electrochemical measurements. A pK(a) value of 10.1-10.4 is observed for the alkaline transition in this oxidized phytocyanin and results in a slightly altered active-site structure, as indicated by changes in the visible and paramagnetic (1)H NMR spectra. Electrochemical studies show that the pK(a) value for this transition in SCu(I) (reduced SCu) is 11.0. These results are compared with those recently obtained for other phytocyanins, and in particular umecyanin. In all cases, the alkaline transition is caused by the deprotonation of the surface lysine residue adjacent to the axial ligand. This lysine residue is completely conserved in known phytocyanin sequences. Also highlighted in these studies are the remarkable active-site similarities between stellacyanin and umecyanin.

Dennison, Christopher; Harrison, Mark D; Lawler, Anne T

2003-01-01

333

New method for counting the number of spanning trees in a two-tree network  

NASA Astrophysics Data System (ADS)

The number of spanning trees is an important quantity characterizing the reliability of a network. Generally, the number of spanning trees in a network can be obtained by directly calculating a related determinant corresponding to the network. However, for a large network, evaluating the relevant determinant is intractable. In this paper, we investigate the number of spanning trees in two-tree networks. We first give a new algorithm which avoids the laborious computation of the determinant for counting the number of spanning trees. Using the algorithm, we can obtain the number of spanning trees of any two-tree network in linear time. The result shows that the computation complexity is O(n), which is better than that of the matrix tree theorem with O(n2), where n is the number of steps. We then characterize two-tree networks with the maximum and minimum numbers of spanning trees. Denote by P(t) and K(t), respectively, the two-tree networks of t+2 vertices with the maximum and minimum numbers of spanning trees. Denote by PA and EN, respectively, the two-tree network of t+2 vertices generated by preferential attachment and by equiprobability attachment. By algorithmic analysis and through simulations, we conjecture that N(K(t))?N(PA)?N(EN)?N(P(t)) as t tends to infinity, where N(G) is the number of spanning trees of G. As an application of the algorithm, we give the formula of the number of spanning trees of a particular small-world network.

Xiao, Yuzhi; Zhao, Haixing

2013-10-01

334

Kinetic KD-trees and longest-side KD-trees  

Microsoft Academic Search

We propose a simple variant of kd-trees, called rank-based kd-trees, for sets of points in Rd. We show that a rank-based kd-tree, like an ordinary kd-tree, supports range search que- ries in O(n1?1\\/d + k) time, where k is the output size. The main advantage of rank-based kd-trees is that they can be efficiently kinetized: the KDS processes O(n2 )e

Mohammad Ali Abam; Mark De Berg; Bettina Speckmann

2007-01-01

335

Millimeter wave backscatter from deciduous trees  

Microsoft Academic Search

Measurements of the millimeter-wave backscatter from deciduous (leafed) trees are explained using a simple scattering model. The backscatter from individual leaves was measured in the laboratory and used to justify the use of an average leaf radar cross section when computing the normalized radar cross section (NRCS) of tree canopies. NRCS measurements of canopies show that the direction in which

Christoph C. Borel; ROBERT E. McINTOSH

1990-01-01

336

Credit scoring with boosted decision trees  

Microsoft Academic Search

The enormous growth experienced by the credit industry has led researchers to develop sophisticated credit scoring models that help lenders decide whether to grant or reject credit to applicants. This paper proposes a credit scoring model based on boosted decision trees, a powerful learning technique that aggregates several deci- sion trees to form a classier given by a weighted majority

A. Bastos

337

Credit scoring with boosted decision trees  

Microsoft Academic Search

The enormous growth experienced by the credit industry has led researchers to develop sophisticated credit scoring models that help lenders decide whether to grant or reject credit to applicants. This paper proposes a credit scoring model based on boosted decision trees, a powerful learning technique that aggregates several decision trees to form a classifier given by a weighted majority vote

Joao Bastos

2008-01-01

338

Global percent tree cover from MODIS data  

Microsoft Academic Search

A global percent tree cover map was created using 500 meter MODIS data. The new map product reveals a detailed depiction of tree cover unprecedented at the global scale. The MODIS data were composited and annual metrics derived describing the phenology of global vegetation. Training data were derived from a global sample of high-resolution imagery which were resampled to the

M. C. Hansen; R. S. DeFries; J. R. Townshend; R. Sohlberg; M. Carroll; C. Dimiceli

2002-01-01

339

Quad Tree Structures for Image Compression Applications.  

ERIC Educational Resources Information Center

Presents a class of distortion controlled vector quantizers that are capable of compressing images so they comply with certain distortion requirements. Highlights include tree-structured vector quantizers; multiresolution vector quantization; error coding vector quantizer; error coding multiresolution algorithm; and Huffman coding of the quad-tree

Markas, Tassos; Reif, John

1992-01-01

340

Employing Linear Regression in Regression Tree Leaves  

Microsoft Academic Search

. The advantage of using linear regressionin the leaves of a regression tree is analysed in thepaper. It is carried out how this modification affectsthe construction, pruning and interpretation of a regressiontree. The modification is tested on artificialand real-life domains. The results show that the modificationis beneficial as it leads to smaller classificationerrors of induced regression trees. Keywords: machinelearning, TDIDT,

Aram Karalic

1992-01-01

341

Computing steiner minimum trees in Hamming metric  

Microsoft Academic Search

Computing Steiner minimum trees in Hamming metric is a well studied problem that has applications in several fields of science such as computational linguistics and computational biology. Among all methods for finding such trees, algorithms using variations of a branch and bound method developed by Penny and Hendy have been the fastest for more than 20 years. In this paper

Ernst Althaus; Rouven Naujoks

2006-01-01

342

Mosses on a tree in forest habitat  

NSDL National Science Digital Library

Mosses require moisture and nutrients to grow (such as moist soil or tree bark). They anchor to tree bark with rhizoids, which are root-like structures lacking phloem and xylem. Mosses are able to lose most of their moisture without dying.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-13

343

Linear Trees and RNA Secondary Structure  

Microsoft Academic Search

The total number of RNA secondary structures of a given length with a fixed number of base pairs is computed, under the assumption that all base pairs can occur. This is done by establishing a one-to-one correspondence between secondary structures and trees. A duality operator on trees is presented, which explains a symmetry in the numbers counting secondary structures.

William R. Schmitt; Michael S. Waterman

1994-01-01

344

Reconstruction of Cell Lineage Trees in Mice  

Microsoft Academic Search

The cell lineage tree of a multicellular organism represents its history of cell divisions from the very first cell, the zygote. A new method for high-resolution reconstruction of parts of such cell lineage trees was recently developed based on phylogenetic analysis of somatic mutations accumulated during normal development of an organism. In this study we apply this method in mice

Adam Wasserstrom; Rivka Adar; Gabi Shefer; Dan Frumkin; Shalev Itzkovitz; Tomer Stern; Irena Shur; Lior Zangi; Shai Kaplan; Alon Harmelin; Yair Reisner; Dafna Benayahu; Eldad Tzahor; Eran Segal; Ehud Shapiro

2008-01-01

345

Water treeing - filled versus unfilled cable insulation  

Microsoft Academic Search

Attempts to make XLPE increasingly resistant to water tree growth have involved additives, which decrease hydrophobicity and make the XLPE more like EPR. EPS are evolving through improved processing, clay compatibilization, etc. to reduce losses while retaining the inherent water tree resistance. Thus in the end, the two technologies appear to be moving toward the \\

Steven Boggs; James Xu

2001-01-01

346

Human Tracking with Mixtures of Trees  

Microsoft Academic Search

Tree-structured probabilistic models admit simple, fast in- ference. However, they are not well suited to phenomena such as occlusion, where multiple components of an object may disappear simultaneously. Mixtures of trees appear to address this problem, at the cost of representing a large mixture. We demonstrate an efficient and compact repre- sentation of this mixture, which admits simple learning and

Sergey Ioffe; David A. Forsyth

2001-01-01

347

The Tree Man: Robert Mazibuko's Story.  

ERIC Educational Resources Information Center

This book for beginning readers highlights Robert Mazibuko, the "Tree Man," who spent his life teaching people how to enrich the soil and plant vegetables and trees. Born in South Africa in 1904, he lived on a farm, learning to work with livestock, raise crops, and share with the community. In college, his professor of agriculture provided a…

Bloch, Joanne, Ed.

348

Adaptive aspects of tree crown geometry  

SciTech Connect

This work attempts to account for the multiplicity of tree crown forms in terms of a biological cost-benefit model in which cost is accounted for in terms of the mass of the wood of the tree and benefit is derived from the crown's efficiency as a solar collector. Methods are developed to describe complex crown shapes, to describe important aspects of complex branching systems, and to describe the three-dimensional distribution of light in forest and open habitats. Data on branching-system geometry was taken from felled trees, and data on overall crown form was taken from photographs of open-grown trees along a latitudinal transect. Computer programs were developed that can iteratively simulate tree growth based on any set of environmental and species-specific parameters. The results of simulations may be produced in printed and graphical form in ways that enable comparison to observed tree crowns. Observed north-south clines in crown form for Juniperus and Pinus are analyzed in terms of the model, and various insights into crown geometry, tree ecology, and tree physiology are won. The cost-benefit model is a powerful tool for understanding crown form and has great potential for future research.

Meiss, M.M.

1983-01-01

349

PCFG models of linguistic tree representations  

Microsoft Academic Search

The kinds of tree representations used in a treebank corpus can have a dramatic effect on performance of a parser based on the PCFG estimated from that corpus, causing the estimated likelihood of a tree to differ substantially from its frequency in the training corpus. This paper points out that the Penn II treebank representations are of the kind predicted

Mark Johnson

1998-01-01

350

BOAT-Optimistic Decision Tree Construction  

Microsoft Academic Search

Classification is an important data mining problem. Given a training databaseof records, each tagged with a class label, the goal of classification is tobuild a concise model that can be used to predict the class label of future,unlabeled records. A very popular class of classifiers are decision trees. Allcurrent algorithms to construct decision trees, including all main-memoryalgorithms, make one scan

Johannes Gehrke; Venkatesh Ganti; Raghu Ramakrishnan; Wei-Yin Loh

1999-01-01

351

Percolation on general trees and HIV modeling  

NASA Astrophysics Data System (ADS)

Percolation on a general tree is studied. A general tree is used to model the transition from HIV infection into AIDS and to explain the large differences of the transition time from one patient to another. HIV has some autoimmune effects due to its low antigenic mutants. Fuzzy mathematics is used to explain these effects.

Ahmed, E.; Agiza, H. N.

1996-12-01

352

Efficiently mining frequent trees in a forest  

Microsoft Academic Search

Mining frequent trees is very useful in domains like bioinformatics, web mining, mining semistructured data, and so on. We formulate the problem of mining (embedded) subtrees in a forest of rooted, labeled, and ordered trees. We present TREEMINER, a novel algorithm to discover all frequent subtrees in a forest, using a new data structure called scope-list. We contrast TREEMINER with

Mohammed Javeed Zaki

2002-01-01

353

Spatiotemporal Relational Probability Trees: An Introduction  

Microsoft Academic Search

We introduce spatiotemporal relational probability trees (SRPTs), probability estimation trees for relational data that can vary in both space and time. The SRPT algo- rithm addresses the exponential increase in search complex- ity through sampling. We validate the SRPT using a sim- ulated data set and we empirically demonstrate the SRPT algorithm on two real-world data sets.

Amy Mcgovern; Nathan C. Hiers; Matthew W. Collier; David J. Gagne II; Rodger A. Brown

2008-01-01

354

Generation of Binary Trees from Ballot Sequences  

Microsoft Academic Search

An efficient algorithm for generating and indexing all shapes of n-noded binary trees is described The algorithm is based on a correspondence between binary trees and the class of stack-sortable permutations. together with a representation of such permutatmns as ballot sequences Justification for the related procedures is given, and their efficiency estabhshed by comparison to other approaches

Doron Rotem; Yaakov L. Varol

1978-01-01

355

Pesticide bioconcentration modelling for fruit trees  

Microsoft Academic Search

The model presented allows simulating the pesticide concentration evolution in fruit trees and estimating the pesticide bioconcentration factor in fruits. Pesticides are non-ionic organic compounds that are degraded in soils cropped with woody species, fruit trees and other perennials. The model allows estimating the pesticide uptake by plants through the water transpiration stream and also the time in which maximum

Lourival Costa Paraíba

2007-01-01

356

Enumeration of End-Labeled Trees.  

National Technical Information Service (NTIS)

Labeled trees with unlabeled end-points were counted previously. Moon enumerated connected labeled graphs with unlabeled end-points. In this note we examine the complementary problem of counting trees in which only the endpoints are labeled, and in so doi...

A. Mowshowitz F. Harary

1975-01-01

357

Regular trees in random regular graphs  

Microsoft Academic Search

We investigate the size of the embedded regular tree rooted at a vertex in a $d$ regular random graph. We show that almost always, the radius of this tree will be ${1\\/2}\\\\log n$, where $n$ is the number of vertices in the graph. And we give an asymptotic estimate for Gauss' Hypergeometric Function.

Eran Makover; Jeffrey McGowan

2006-01-01

358

TAX: A Tree Algebra for XML  

Microsoft Academic Search

Querying XML has been the subject of much recent investigation. A formal bulk algebra is essential for applying database-style optimization to XML queries. We develop such an algebra, called TAX (Tree Algebra for XML), for manipulating XML data, modeled as forests of labeled ordered trees. Motivated both by aesthetic considerations of intuitiveness, and by efficient computability and amenability to optimization,

H. V. Jagadish; Laks V. S. Lakshmanan; Divesh Srivastava; Keith Thompson

2001-01-01

359

FAULT TREE ANALYSIS FOR SYSTEM RELIABILITY  

Microsoft Academic Search

Fault Tree Analysis (FTA) can be used to predict and prevent accidents or as an investigative tool after an event. FTA is an analytical methodology that uses a graphical model to display the analysis process. Visually a fault tree is built by special symbols, some derived from Boolean algebra. Consequently, the resulting model resembles a logic diagram or a flow

Ercüment N. D?ZDAR

360

Algorithmic fault tree synthesis for control loops  

Microsoft Academic Search

Efficient process control is an integral part of the design and operation of a safe and productive chemical plant. It is crucial for fault tree analysis since control systems are designed to prevent process deviations. How to handle control loops is a major concern in the research of computer-aided fault tree synthesis for the chemical process industry (CPI). This paper

Yanjun Wang; William J Rogers; Harry H West; M. Sam Mannan

2003-01-01

361

Symbolic Fault Tree Analysis for Reactive Systems  

Microsoft Academic Search

Fault tree analysis is a traditional and well-established technique for analyzing system design and robustness. Its purpose is to identify sets of basic events, called cut sets, which can cause a given top level event, e.g. a system malfunction, to occur. Generating fault trees is particularly critical in the case of reactive systems, as hazards can be the result of

Marco Bozzano; Alessandro Cimatti; Francesco Tapparo

2007-01-01

362

CRITIQUE OF CARBON BASED TREE GROWTH MODELS  

EPA Science Inventory

Simulation models of the processes that control carbohydrate balance in coniferous trees are reviewed, and their appropriateness for assessing pollution effects is considered. Currently such models are at the forefront of attempts to simulate the growth process of trees, but they...

363

Using Decision Trees for Coreference Resolution  

Microsoft Academic Search

This paper describes RESOLVE, a s>stem that uses decision trees to learn how to classify coref- erent phrases in the domain of business joint ventures An experiment is presented in which the performance of RESOLVE is compared to the performance of a manually engineered set of rules for the same task The results show that decision trees achieve higher performance

Joseph F. Mccarthy; Wendy G. Lehnert

1995-01-01

364

Aboveground Tree Biomass Statistics for Maine: 1982.  

National Technical Information Service (NTIS)

A statistical report based on the third forest survey of Maine conducted in 1980-82. Results of the survey are displayed in 87 tables containing estimates of timberland area, timber volume, numbers of trees, and aboveground tree biomass. These estimates w...

A. M. Malley E. H. Wharton T. S. Frieswyk

1985-01-01

365

A Dichromatic Framework for Balanced Trees  

Microsoft Academic Search

In this paper we present a uniform framework for the implementation and study of balanced tree algorithms. We show how to imbed in this framework the best known balanced tree techniques and then use the framework to develop new algorithms which perform the update and rebalancing in one pass, on the way down towards a leaf. We conclude with a

Leonidas J. Guibas; Robert Sedgewick

1978-01-01

366

Applications of Path Compression on Balanced Trees  

Microsoft Academic Search

Several fast algorithms are presented for computing functions defined on paths in trees under various assumpuons. The algorithms are based on tree mampulatton methods first used to efficiently represent equivalence relations. The algorithms have O((m + n)a(m + n, n)) running tunes, where m and n are measures of the problem size and a Is a functional reverse of Ackermann's

Robert Endre Tarjan

1979-01-01

367

Dynamic Positional Trees for Structural Image Analysis  

Microsoft Academic Search

Dynamic positional trees are a signicant extensionof dynamic trees, incorporating movablenodes. This addition makes sequencetracking viable within the model, but requiresa new formulation to incorporate the priorover positions. The model is implemented usinga structured variational procedure, and isillustrated on synthetic raytraced images andimage sequences.We consider the problem of structural image analysisand in particular the inference of scene propertiesfrom image...

Amos J. Storkey; Christopher K. i. Williams

2000-01-01

368

Combining Classifiers with Meta Decision Trees  

Microsoft Academic Search

The paper introduces meta decision trees (MDTs), a novel method for combining multiple classifiers. Instead of giving a prediction, MDT leaves specify which classifier should be used to obtain a prediction. We present an algorithm for learning MDTs based on the C4.5 algorithm for learning ordinary decision trees (ODTs). An extensive experimental evaluation of the new algorithm is performed on

Robert E. Schapire

369

Enlarging the Margins in Perceptron Decision Trees  

Microsoft Academic Search

Capacity control in perceptron decision trees is typically performed by controlling their size. We prove that other quantities can be as relevant to reduce their flexibility and combat overfitting. In particular, we provide an upper bound on the generalization error which depends both on the size of the tree and on the margin of the decision nodes. So enlarging the

Kristin P. Bennett; Nello Cristianini; John Shawe-taylor; Donghui Wu

2000-01-01

370

How Trees Help the Power Company!  

ERIC Educational Resources Information Center

Proposes the utilization of graph theory to solve optimization problems. Defines the notion of spanning trees and presents two algorithms to determine optimization of a spanning tree. Discusses an example to connect towns by power transmission lines at minimum cost. (MDH)

King, Rik

1992-01-01

371

Bootstrap Confidence Levels for Phylogenetic Trees  

Microsoft Academic Search

Evolutionary trees are often estimated from DNA or RNA sequence data. How much confidence should we have in the estimated trees? In 1985, Felsenstein [Felsenstein, J. (1985) Evolution 39, 783-791] suggested the use of the bootstrap to answer this question. Felsenstein's method, which in concept is a straightforward application of the bootstrap, is widely used, but has been criticized as

Bradley Efron; Elizabeth Halloran; Susan Holmes

1996-01-01

372

Design and Realization of Directory Tree Navigation  

Microsoft Academic Search

There are many Web-based curriculums in which the chapter navigation is designed as directory tree. In most cases, developing the directory tree requires a large quantity of code and the chapter navigation lacks flexibility as well as extensibility. In our method, we rationally integrated EXTJS with WEBWORK in the JAVA platform. The EXTJS code was directly introduced on the JSP

Hexiao Huang; Rener Zheng; Lei Wang; Haijian Chen; Jianhan Peng

2009-01-01

373

Nearest Neighbor Search using Kd-trees  

Microsoft Academic Search

We suggest a simple modification to the kd-tree search algorithm for nearest neighbor search re- sulting in an improved performance. The Kd-tree data structure seems to work well in finding nearest neighbors in low dimensions but its performance degrades even if the number of dimensions increases to more than three. Since the exact nearest neighbor search problem suffers from the

Rina Panigrahy

374

On Improving Kd Tree for Ray Shooting  

Microsoft Academic Search

Efficient ray shooting algorithm is inherently required by many computer graphics algorithms, particularly in image synthesis. Practical ray shooting algorithms aiming at the average-case complexity use some underlying spatial data structure such as -tree. We show the new termi- nation criteria algorithm that improves the space and time complexity of the -tree construction. It provides efficient ray-shooting queries and does

Vlastimil Havran; Jirí Bittner

2002-01-01

375

Alcohol co-production from tree crops  

SciTech Connect

A concept for the sustainable production of alcohol from fermentable substrates produced on an annual basis by the reproductive organs (pods, fruits, nuts, berries, etc.) of tree crops is presented. The advantages of tree-crop systems include suitability for use on marginal land, potential productivity equivalent to row crops, minimal maintenance and energy-input requirements, environmental compatibility, and the possibility of co-product production. Honeylocust, mesquite, and persimmon are examined as potential US tree-crop species. Other species not previously considered, including osage orange and breadfruit, are suggested as tree-crop candidates for North America and the tropical developing world, respectively. Fermentation of tree-crop organs and the economics of tree-crop systems are also discussed. Currently the greatest area of uncertainty lies in actual pod or fruit yields one can expect from large tree farms under real life conditions. However, ballpark ethanol yield estimates of from 880 to 3470 l hectare/sup -1/ (94 to 400 gal acre/sup -1/) justify further consideration of tree crop systems.

Seibert, M.; Folger, G.; Milne, T.

1982-06-01

376

Alternation-free modal mu-calculus for data trees  

Microsoft Academic Search

An alternation-free modal mu-calculus over data trees is introduced and studied. A data tree is an unranked ordered tree whose every node is labelled by a letter from a finite alphabet and an element (\\

Marcin Jurdzinski; Ranko Lazic

2007-01-01

377

Global percent tree cover from MODIS data  

NASA Astrophysics Data System (ADS)

A global percent tree cover map was created using 500 meter MODIS data. The new map product reveals a detailed depiction of tree cover unprecedented at the global scale. The MODIS data were composited and annual metrics derived describing the phenology of global vegetation. Training data were derived from a global sample of high-resolution imagery which were resampled to the 500 meter grid. This continuous training data set was then input to a regression tree algorithm. The regression tree outputs were modified using a stepwise regression model and a bias function. Also generated were layers describing leaf type and leaf morphology of tree cover. Using the same procedure, percent broadleaf and needleleaf and percent evergreen and deciduous layers were created. Results show that the MODIS data offer a much improved depiction of land cover heterogeneity than AVHRR data.

Hansen, M. C.; DeFries, R. S.; Townshend, J. R.; Sohlberg, R.; Carroll, M.; Dimiceli, C.

2002-05-01

378

TreeViewJ: An application for viewing and analyzing phylogenetic trees  

PubMed Central

Background Phylogenetic trees are widely used to visualize evolutionary relationships between different organisms or samples of the same organism. There exists a variety of both free and commercial tree visualization software available, but limitations in these programs often require researchers to use multiple programs for analysis, annotation, and the production of publication-ready images. Results We present TreeViewJ, a Java tool for visualizing, editing and analyzing phylogenetic trees. The software allows researchers to color and change the width of branches that they wish to highlight, and add names to nodes. If collection dates are available for taxa, the software can map them onto a timeline, and sort the tree in ascending or descending date order. Conclusion TreeViewJ is a tool for researchers to visualize, edit, "decorate," and produce publication-ready images of phylogenetic trees. It is open-source, and released under an GPL license, and available at .

Peterson, Matthew W; Colosimo, Marc E

2007-01-01

379

Decision Tree for Optimization Software  

NSDL National Science Digital Library

H.D. Mittelmann from the Department of Math and Statistics at Arizona State University and P. Spellucci from Department of Mathematics at Technical University Darmstadt have posted this guide entitled, Decision Tree for Optimization Software. The guide "aims at helping you identify ready to use solutions for your optimization problem, or at least to find some way to build such a solution using work done by others." The online document is organized into sections covering specific software problems, a collection of test results and performance tests, and example files to use with existing software. The authors also list information on available books and tutorials, some of which are online, as well as various software tools to assist in formulating an optimization problem or simplifying its solution. Those tools listed in the Web-submission section are available to try directly via the Internet.

380

Electrical signals in avocado trees  

PubMed Central

Plant responses to environmental changes are associated with electrical excitability and signaling; automatic and continuous measurements of electrical potential differences (?EP) between plant tissues can be effectively used to study information transport mechanisms and physiological responses that result from external stimuli on plants. The generation and conduction of electrochemical impulses within plant different tissues and organs, resulting from abiotic and biotic changes in environmental conditions is reported. In this work, electrical potential differences are monitored continuously using Ag/AgCl microelectrodes, inserted 5 mm deep into sapwood at two positions in the trunks of several Avocado trees. Electrodes are referenced to a non polarisable Ag/AgCl microelectrode installed 20 cm deep in the soil. Systematic patterns of ?EP during absolute darkness, day-night cycles and different conditions of soil water availability are discussed as alternative tools to assess early plant stress conditions.

Oyarce, Patricio

2010-01-01

381

Tree array quantum cascade laser.  

PubMed

A monolithic coupling scheme for mid-infrared quantum cascade laser arrays is investigated with respect to brightness enhancement. The tree-shaped resonator enables parallel coupling of six laser elements into a single element by means of several Y-junctions. Phase-locking is observed on the basis of far field analysis, and leads to in-phase emission on both sides of the device. The experimental results match calculated far field profiles and demonstrate a high level of modal control when driven far above threshold. Whereas optical power measurements confirm negligible coupling losses, the slope efficiency is below the theoretically expected value, which is attributed to modal competition. Additional evaluation of near fields and spectral characteristics provides background on the modal dynamics of the sophisticated cavity and reveals limitations to coherent beam combining. The findings pave the way to improved coupling efficiency and brightness scaling of a single facet emitting compact quantum cascade laser array. PMID:19158878

Hoffmann, Leonard K; Klinkmüller, Matthias; Mujagi?, Elvis; Semtsiv, Mykhaylo P; Schrenk, Werner; Masselink, William T; Strasser, Gottfried

2009-01-19

382

Fault trees and imperfect coverage  

NASA Technical Reports Server (NTRS)

A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated exactly. A dynamic state truncation technique is also presented; it produces bounds on the unreliability of the system by considering only part of the state space. Since the model is solved as the state space is generated, the process can be stopped as soon as the desired accuracy is reached.

Dugan, Joanne B.

1989-01-01

383

Pruning a minimum spanning tree  

NASA Astrophysics Data System (ADS)

This work employs various techniques in order to filter random noise from the information provided by minimum spanning trees obtained from the correlation matrices of international stock market indices prior to and during times of crisis. The first technique establishes a threshold above which connections are considered affected by noise, based on the study of random networks with the same probability density distribution of the original data. The second technique is to judge the strength of a connection by its survival rate, which is the amount of time a connection between two stock market indices endures. The idea is that true connections will survive for longer periods of time, and that random connections will not. That information is then combined with the information obtained from the first technique in order to create a smaller network, in which most of the connections are either strong or enduring in time.

Sandoval, Leonidas

2012-04-01

384

Language distance and tree reconstruction  

NASA Astrophysics Data System (ADS)

Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others.

Petroni, Filippo; Serva, Maurizio

2008-08-01

385

75 FR 51507 - WisdomTree Asset Management, Inc., and WisdomTree Trust; Notice of Application  

Federal Register 2010, 2011, 2012, 2013

...812-13733] WisdomTree Asset Management, Inc., and WisdomTree...Applicants: WisdomTree Asset Management, Inc (``WTAM'' or...providing continuous investment management for each Fund's assets. As compensation for...

2010-08-20

386

Urban Tree Effects on Soil Organic Carbon  

PubMed Central

Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ?75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC) and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth) compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C?N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

Edmondson, Jill L.; O'Sullivan, Odhran S.; Inger, Richard; Potter, Jonathan; McHugh, Nicola; Gaston, Kevin J.; Leake, Jonathan R.

2014-01-01

387

Binary space partitioning trees and their uses  

NASA Technical Reports Server (NTRS)

Binary Space Partitioning (BSP) trees have some qualities that make them useful in solving many graphics related problems. The purpose is to describe what a BSP tree is, and how it can be used to solve the problem of hidden surface removal, and constructive solid geometry. The BSP tree is based on the idea that a plane acting as a divider subdivides space into two parts with one being on the positive side and the other on the negative. A polygonal solid is then represented as the volume defined by the collective interior half spaces of the solid's bounding surfaces. The nature of how the tree is organized lends itself well for sorting polygons relative to an arbitrary point in 3 space. The speed at which the tree can be traversed for depth sorting is fast enough to provide hidden surface removal at interactive speeds. The fact that a BSP tree actually represents a polygonal solid as a bounded volume also makes it quite useful in performing the boolean operations used in constructive solid geometry. Due to the nature of the BSP tree, polygons can be classified as they are subdivided. The ability to classify polygons as they are subdivided can enhance the simplicity of implementing constructive solid geometry.

Bell, Bradley N.

1989-01-01

388

Reconciliation of Gene and Species Trees  

PubMed Central

The first part of the paper briefly overviews the problem of gene and species trees reconciliation with the focus on defining and algorithmic construction of the evolutionary scenario. Basic ideas are discussed for the aspects of mapping definitions, costs of the mapping and evolutionary scenario, imposing time scales on a scenario, incorporating horizontal gene transfers, binarization and reconciliation of polytomous trees, and construction of species trees and scenarios. The review does not intend to cover the vast diversity of literature published on these subjects. Instead, the authors strived to overview the problem of the evolutionary scenario as a central concept in many areas of evolutionary research. The second part provides detailed mathematical proofs for the solutions of two problems: (i) inferring a gene evolution along a species tree accounting for various types of evolutionary events and (ii) trees reconciliation into a single species tree when only gene duplications and losses are allowed. All proposed algorithms have a cubic time complexity and are mathematically proved to find exact solutions. Solving algorithms for problem (ii) can be naturally extended to incorporate horizontal transfers, other evolutionary events, and time scales on the species tree.

Rusin, L. Y.; Lyubetskaya, E. V.; Gorbunov, K. Y.; Lyubetsky, V. A.

2014-01-01

389

Tree-hole breeding mosquitoes in Israel.  

PubMed

A survey was conducted to evaluate the number of tree-hole breeding mosquito species and their distribution in the six principal woodland types in Israel. Out of approximately 3,000 mature trees examined, only 38 contained holes that retained water for extended periods of time, and breeding mosquitoes were observed in 27 of them. Two specialized tree-hole breeders, Aedes pulchritarsis Rondani and Aedes geniculatus Oliver, were found breeding at several sites in northern Israel, always at locations 500 m above sea level (a.s.l) and with high annual precipitation. Aedes albopictus Skuse which, in Israel, is known as an opportunistic container breeder, was found in this study to have adapted remarkably well to breeding in tree holes and was found in most forest types investigated and in most tree species which had adequate tree holes. Two other species, Culiseta annulata Schrank and Culex pipiens Linnaeus instars, were found in one of the tree holes, but did not survive to reach maturity. PMID:22548543

Müller, Günter C; Kravchenko, Vasiliy D; Junnila, Amy; Schlein, Yosef

2012-06-01

390

Looking for trees in the forest: summary tree from posterior samples  

PubMed Central

Background Bayesian phylogenetic analysis generates a set of trees which are often condensed into a single tree representing the whole set. Many methods exist for selecting a representative topology for a set of unrooted trees, few exist for assigning branch lengths to a fixed topology, and even fewer for simultaneously setting the topology and branch lengths. However, there is very little research into locating a good representative for a set of rooted time trees like the ones obtained from a BEAST analysis. Results We empirically compare new and known methods for generating a summary tree. Some new methods are motivated by mathematical constructions such as tree metrics, while the rest employ tree concepts which work well in practice. These use more of the posterior than existing methods, which discard information not directly mapped to the chosen topology. Using results from a large number of simulations we assess the quality of a summary tree, measuring (a) how well it explains the sequence data under the model and (b) how close it is to the “truth”, i.e to the tree used to generate the sequences. Conclusions Our simulations indicate that no single method is “best”. Methods producing good divergence time estimates have poor branch lengths and lower model fit, and vice versa. Using the results presented here, a user can choose the appropriate method based on the purpose of the summary tree.

2013-01-01

391

Mechanical Stimuli Regulate the Allocation of Biomass in Trees: Demonstration with Young Prunus avium Trees  

PubMed Central

Background and Aims Plastic tree-shelters are increasingly used to protect tree seedlings against browsing animals and herbicide drifts. The biomass allocation in young seedlings of deciduous trees is highly disturbed by common plastic tree-shelters, resulting in poor root systems and reduced diameter growth of the trunk. The shelters have been improved by creating chimney-effect ventilation with holes drilled at the bottom, resulting in stimulated trunk diameter growth, but the root deficit has remained unchanged. An experiment was set up to elucidate the mechanisms behind the poor root growth of sheltered Prunus avium trees. Methods Tree seedlings were grown either in natural windy conditions or in tree-shelters. Mechanical wind stimuli were suppressed in ten unsheltered trees by staking. Mechanical stimuli (bending) of the stem were applied in ten sheltered trees using an original mechanical device. Key Results Sheltered trees suffered from poor root growth, but sheltered bent trees largely recovered, showing that mechano-sensing is an important mechanism governing C allocation and the shoot–root balance. The use of a few artificial mechanical stimuli increased the biomass allocation towards the roots, as did natural wind sway. It was demonstrated that there was an acclimation of plants to the imposed strain. Conclusions This study suggests that if mechanical stimuli are used to control plant growth, they should be applied at low frequency in order to be most effective. The impact on the functional equilibrium hypothesis that is used in many tree growth models is discussed. The consequence of the lack of mechanical stimuli should be incorporated in tree growth models when applied to environments protected from the wind (e.g. greenhouses, dense forests).

Coutand, Catherine; Dupraz, Christian; Jaouen, Gaelle; Ploquin, Stephane; Adam, Boris

2008-01-01

392

Comprehensive Decision Tree Models in Bioinformatics  

PubMed Central

Purpose Classification is an important and widely used machine learning technique in bioinformatics. Researchers and other end-users of machine learning software often prefer to work with comprehensible models where knowledge extraction and explanation of reasoning behind the classification model are possible. Methods This paper presents an extension to an existing machine learning environment and a study on visual tuning of decision tree classifiers. The motivation for this research comes from the need to build effective and easily interpretable decision tree models by so called one-button data mining approach where no parameter tuning is needed. To avoid bias in classification, no classification performance measure is used during the tuning of the model that is constrained exclusively by the dimensions of the produced decision tree. Results The proposed visual tuning of decision trees was evaluated on 40 datasets containing classical machine learning problems and 31 datasets from the field of bioinformatics. Although we did not expected significant differences in classification performance, the results demonstrate a significant increase of accuracy in less complex visually tuned decision trees. In contrast to classical machine learning benchmarking datasets, we observe higher accuracy gains in bioinformatics datasets. Additionally, a user study was carried out to confirm the assumption that the tree tuning times are significantly lower for the proposed method in comparison to manual tuning of the decision tree. Conclusions The empirical results demonstrate that by building simple models constrained by predefined visual boundaries, one not only achieves good comprehensibility, but also very good classification performance that does not differ from usually more complex models built using default settings of the classical decision tree algorithm. In addition, our study demonstrates the suitability of visually tuned decision trees for datasets with binary class attributes and a high number of possibly redundant attributes that are very common in bioinformatics.

Stiglic, Gregor; Kocbek, Simon; Pernek, Igor; Kokol, Peter

2012-01-01

393

Tree Edit Distance Problems: Algorithms and Applications to Bioinformatics  

NASA Astrophysics Data System (ADS)

Tree structured data often appear in bioinformatics. For example, glycans, RNA secondary structures and phylogenetic trees usually have tree structures. Comparison of trees is one of fundamental tasks in analysis of these data. Various distance measures have been proposed and utilized for comparison of trees, among which extensive studies have been done on tree edit distance. In this paper, we review key results and our recent results on the tree edit distance problem and related problems. In particular, we review polynomial time exact algorithms and more efficient approximation algorithms for the edit distance problem for ordered trees, and approximation algorithms for the largest common sub-tree problem for unordered trees. We also review applications of tree edit distance and its variants to bioinformatics with focusing on comparison of glycan structures.

Akutsu, Tatsuya

394

The decision tree approach to classification  

NASA Technical Reports Server (NTRS)

A class of multistage decision tree classifiers is proposed and studied relative to the classification of multispectral remotely sensed data. The decision tree classifiers are shown to have the potential for improving both the classification accuracy and the computation efficiency. Dimensionality in pattern recognition is discussed and two theorems on the lower bound of logic computation for multiclass classification are derived. The automatic or optimization approach is emphasized. Experimental results on real data are reported, which clearly demonstrate the usefulness of decision tree classifiers.

Wu, C.; Landgrebe, D. A.; Swain, P. H.

1975-01-01

395

Tree Death Study's Climate Change Connections  

ScienceCinema

What are the exact physiological mechanisms that lead to tree death during prolonged drought and rising temperatures? These are the questions that scientists are trying to answer at a Los Alamos National Laboratory research project called SUMO. SUMO stands for SUrvival/MOrtality study; it's a plot of land on the Lab's southern border that features 18 climate controlled tree study chambers and a large drought structure that limits rain and snowfall. Scientists are taking a wide variety of measurements over a long period of time to determine what happens during drought and warming, and what the connections and feedback loops might be between tree death and climate change.

McDowell, Nate

2014-06-25

396

Tree Rings as Records of the Past  

NSDL National Science Digital Library

In this activity students will examine sections of cut trees. They will observe and describe the difference between early and late wood, make a guess about the age of the tree, determine the actual age by counting the rings, and identify the rings that represent the years the student, the student's parents, and the student's grandparents were born, or years of historical importance. In addition, students may identify the narrowest rings, then check precipitation records to see if these coincide with years of low rainfall. They will discover that trees grow in diameter by producing new wood in the layer just beneath their bark.

Bjornerud, Marcia

397

Photosynthesis, Trees, and the Greenhouse Effect  

NSDL National Science Digital Library

In this lesson plan students will study photosynthesis and then transfer their understanding of this topic to a consideration of how trees can help reduce the negative impacts of the greenhouse effect. They will read a webpage describing the greenhouse effect, the role of carbon dioxide as a greenhouse gas, and the role of humans in exacerbating this effect. Students will also browse the website of an organization that sponsors tree planting programs and consider how these programs might help reduce or slow down the increase of the greenhouse effect. They will conclude by writing paragraphs telling younger kids about the benefits of trees and plants.

398

Tree Death Study's Climate Change Connections  

SciTech Connect

What are the exact physiological mechanisms that lead to tree death during prolonged drought and rising temperatures? These are the questions that scientists are trying to answer at a Los Alamos National Laboratory research project called SUMO. SUMO stands for SUrvival/MOrtality study; it's a plot of land on the Lab's southern border that features 18 climate controlled tree study chambers and a large drought structure that limits rain and snowfall. Scientists are taking a wide variety of measurements over a long period of time to determine what happens during drought and warming, and what the connections and feedback loops might be between tree death and climate change.

McDowell, Nate

2012-09-10

399

Big tree : have you ever seen a tree big enough to drive a car through?  

NSDL National Science Digital Library

In this activity, students are given the girth and height of 10 National Champion giant trees and asked to determine which of the trees is large enough for a car to drive through. The activity, from the Figure This! list of 80 math challenges, also asks students to apply what they have learned to estimate the height of a tree in their neighborhood. It suggests that the student make a table to relate information about tree girth, circumference, and diameter to help determine which giant trees are big enough for a car to drive through. The importance of measurement formulas to careers in biology, construction, and publishing is noted. The page features links to a solution hint, the solution, related math questions, and resources for learning more about trees. Copyright 2005 Eisenhower National Clearinghouse

Engineering, National A.; National Council of Teachers of Mathematics (NCTM); Communications, Widmeyer

2002-01-01

400

Distributed game-tree searching  

SciTech Connect

Conventional parallelizations of the alpha-beta ({alpha}{beta}) algorithm have met with limited success. Implementations suffer primarily from the synchronization and search overheads of parallelization. This paper describes a parallel {alpha}{beta} searching program that achieves high performance through the use of four different types of processes: Controllers, Searchers, Table Managers, and Scouts. Synchronization is reduced by having Controller process reassigning idle processes to help out busy ones. Search overhead is reduced by having two types of parallel table management: global Table Managers and the periodic merging and redistribution of local tables. Experiments show that nine processors can achieve 5.67-fold speedups but beyond that, additional processors provide diminishing returns. Given that additional resources are of little benefit, speculative computing is introduced as a means of extending the effective number of processors that can be utilized. Scout processes speculatively search ahead in the tree looking for interesting features and communicate this information back to the {alpha}{beta} program. In this way, the effective search depth is extended. These ideas have been tested experimentally and empirically as part of the chess program ParaPhoenix.

Schaeffer, J. (Computing Science Dept., Univ. of Alberta, Alberta (CA))

1989-02-01

401

Photosynthetic Action Spectra of Trees  

PubMed Central

Comparative isoenergetic action spectra of net photosynthesis for intact, current year foliage of five tree species were determined from 400 to 710 nm by CO2 exchange analysis. The blue (400 to 500 nm) peak of net photosynthetic activity for the green broadleaves of red alder (Alnus rubra Bong.) was reduced to a plateau for the green needle-leaves of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and Sitka spruce (Picea sitchensis [Bong.] Carr.), a shoulder for the blue-green needles of Colorado spruce (Picea pungens Engelm.), and a reduced shoulder for the blue-white needles of Blue spruce (Picea pungens var. hoospii). These differences were attributable neither to a differential blue light stimulation of photorespiration nor to a differential presence of a nonplastid screening pigment. The conifers all had similar carotenoid-chlorophyll ratios, with approximately 50% more carotenoid relative to chlorophyll as compared to red alder. Blue light absorption and low efficiency of energy transfer by the carotenoids probably accounts for the low net photosynthetic activity of the green conifers in blue light as compared to red alder. Leaf form per se (broad versus needle) had no distinguishable influence on these results.

Clark, John B.; Lister, Geoffrey R.

1975-01-01

402

Extended Full Computation-Tree Logic with Sequence Modal Operator: Representing Hierarchical Tree Structures  

NASA Astrophysics Data System (ADS)

An extended full computation-tree logic, CTLS*, is introduced as a Kripke semantics with a sequence modal operator. This logic can appropriately represent hierarchical tree structures where sequence modal operators in CTLS* are applied to tree structures. An embedding theorem of CTLS* into CTL* is proved. The validity, satisfiability and model-checking problems of CTLS* are shown to be decidable. An illustrative example of biological taxonomy is presented using CTLS* formulas.

Kamide, Norihiro; Kaneiwa, Ken

403

Tree mixture effects on aboveground nutrient pools of trees in an experimental plantation in Panama  

Microsoft Academic Search

Mixed plantations might contribute to sustainable land use because of complementary nutrient use. Our objective was to assess\\u000a the nutrient economy of five native tree species and their response to different neighbor trees in an experimental plantation\\u000a in Panama. In our study, H. crepitans was the least nutrient efficient tree species. H. crepitans produced less biomass in mixtures than in

Yvonne Oelmann; Catherine Potvin; Timo Mark; Lisa Werther; Simone Tapernon; Wolfgang Wilcke

2010-01-01

404

Production rates and costs of whole-tree, tree length, and log-length skyline thinning  

Microsoft Academic Search

Production rates and costs were determined for harvesting smallwood by different methods of skyline yarding: whole-tree (yarding with limbs and tops), tree-length (bucking done on the landing), and log-length (limbing, topping, and bucking done on the slope). A rubber-tired skidder was used to swing and sort the variously cut trees from the landing to a site on the haul road

N. E. Putman; L. D. Kellogg; E. D. Olsen

1984-01-01

405

Medical Image Segmentation using a Tree Model.  

National Technical Information Service (NTIS)

A model-driven, multiscale medical image segmentation system is presented. A tree representation is calculated for the image, using a modification of the immersion algorithm used for watersheds calculation. Segmentation is carried out by a matching proces...

V. Grau M. Alcaniz C. Monserrat M. C. Juan J. A. Gil

2001-01-01

406

Circular Drawings of Rooted Trees. Information Systems.  

National Technical Information Service (NTIS)

We describe an algorithm producing circular layouts for trees, that is drawings, where subtrees of a node lie within circles, and these circles are themselves placed on the circumference of a circle. The complexity and methodology of our algorithm compare...

G. Melancon I. Herman

1998-01-01

407

Fruit and Tree Nuts Outlook, June 2012.  

National Technical Information Service (NTIS)

Provides current intelligence and forecasts the effects of changing conditions in the U.S. fruit and tree nuts sector. Topics include production, consumption, shipments, prices received, and more. This seasons Southern Hemisphere blueberry shipments to th...

A. Perez K. Plattner

2012-01-01

408

Repeatability of TREES rotor bore inspection system  

SciTech Connect

The repeatability of near-bore flaw detection and sizing of the Turbine Rotor Examination and Evaluation System (TREES) developed in EPRI RP502 was examined by making many repeat scans of sample blocks containing fatigue cracks and embedded spherical- and disk-shaped flaws of various sizes. Comparison data was also collected manually using the Bore Ultrasonic Characterization System (BUCS). Approximately 1500 measurements were taken with TREES and 1200 were taken with BUCS during the course of this study. The results of this work showed that TREES consistently detected flaws in the near-bore region. TREES determined the radial extent of flaws with associated standard deviations of 18% for fatigue cracks, 30% for embedded spherical beads and 18 to 28% for embedded disk-shaped reflectors. Corresponding BUCS measurements showed larger measurement spreads in each flaw classification.

Ammirato, F.V.

1982-11-01

409

Interaction Trees with Censored Survival Data  

PubMed Central

We propose an interaction tree (IT) procedure to optimize the subgroup analysis in comparative studies that involve censored survival times. The proposed method recursively partitions the data into two subsets that show the greatest interaction with the treatment, which results in a number of objectively defined subgroups: in some of them the treatment effect is prominent while in others the treatment may have a negligible or even negative effect. The resultant tree structure can be used to explore the overall interaction between treatment and other covariates and help identify and describe possible target populations on which an experimental treatment demonstrates desired efficacy. We follow the standard CART (Breiman, et al., 1984) methodology to develop the interaction tree structure. Variable importance information is extracted via random forests of interaction trees. Both simulated experiments and an analysis of the primary billiary cirrhosis (PBC) data are provided for evaluation and illustration of the proposed procedure.

Su, Xiaogang; Zhou, Tianni; Yan, Xin; Fan, Juanjuan; Yang, Song

2008-01-01

410

Asian Longhorned Beetle and Its Host Trees.  

National Technical Information Service (NTIS)

This pictorial guide provides basic information for identifying the Asian longhorned beetle, its injury characteristics, and its common host trees. The guide will help users detect the beetle in both urban and forested settings.

2012-01-01

411

Evolutionary and Ecological Trees and Networks  

NASA Astrophysics Data System (ADS)

Evolutionary relationships between species are usually represented in phylogenies, i.e. evolutionary trees, which are a type of networks. The terminal nodes of these trees represent species, which are made of individuals and populations among which gene flow occurs. This flow can also be represented as a network. In this paper we briefly show some properties of these complex networks of evolutionary and ecological relationships. First, we characterize large scale evolutionary relationships in the Tree of Life by a degree distribution. Second, we represent genetic relationships between individuals of a Mediterranean marine plant, Posidonia oceanica, in terms of a Minimum Spanning Tree. Finally, relationships among plant shoots inside populations are represented as networks of genetic similarity.

Hernández-García, Emilio; Herrada, E. Alejandro; Rozenfeld, Alejandro F.; Tessone, Claudio J.; Eguíluz, Víctor M.; Duarte, Carlos M.; Arnaud-Haond, Sophie; Serra~O, Ester

2007-05-01

412

On the Optimality of Huffman Trees.  

National Technical Information Service (NTIS)

Huffman's well-known algorithm for the construction of optimal search trees is shown to have a more general optimality property than was previously known. A corollary of this general optimality property yields explicitly the optimal policy for the dynamic...

C. R. Glassey R. M. Karp

1974-01-01

413

Worms and Trees: An Exciting Adventure.  

ERIC Educational Resources Information Center

Outlines procedures for using silkworms in elementary science, mathematics, history, ecology, social studies, language arts, art, and physical education. Also focuses on the silkworm's use of the mulberry tree. (DDR)

El Harim, Jean Love

1997-01-01

414

Phloem Exudation Studies in Selected Woody Trees.  

National Technical Information Service (NTIS)

Chelating agents, particularly EDTA, were tested for their effectiveness in enhancing the exudation of phloem sugars from selected woody tree species. Of the species selected, Fraxinus uhdei (Evergreen Ash) proved most useful for exudation studies. Experi...

L. R. Costello

1980-01-01

415

Electrochemical Treeing in Cable. Final Report.  

National Technical Information Service (NTIS)

Results are presented of an investigation of electrochemical treeing in solid dielectric insulated cables performed between May, 1973 and March, 1977 for the Electric Power Research Institute. The purpose of the work was to establish the influence of vari...

N. Nagu inivas H. C. Deopken A. L. McKean M. C. Biskeborn

1978-01-01

416

Optimal parallel evaluation of AND trees  

SciTech Connect

AND-tree evaluation is an important technique in artificial intelligence and operations research. An example is the divide-and-conquer algorithm, which can be considered the evaluation of a precedence graph consisting of two opposing AND trees. In this paper, the optimal degree of parallelism for evaluating any given AND tree is quantitatively analyzed. The efficiency analysis is based on both preemptive and on preemptive critical-path scheduling algorithms. It is found that the optimal degree of parallelism depends on the complexity of the problem to be solved, the shape of the precedence graph, and the task-time distribution along each path. The major results consist of showing the optimality of the preemptive critical-path scheduling algorithm for evaluating any given AND tree on a fixed number of processors, and tight bounds on the number of processors within which the number of processors leading to the optimal processor-time efficiency can be sought efficiently.

Wah, B.W. (Illinois Univ., Urbana, IL (USA). Dept. of Electrical and Computer Engineering); Li, G.J. (Institute of Computing Technology, Academia Sinica, P.O. Box 2704-1, Beijing (CN))

1990-09-01

417

Trees protected villages from tsunami waves  

NSDL National Science Digital Library

In India, trees growing along the coastline helped to protect villages from the "walls of water" or tsunami waves that were triggered by a powerful earthquake that struck beneath the Indian Ocean on 26 December 2004, scientists have discovered.

American Association for the Advancement of Science (AAAS;)

2005-10-27

418

Tree Growth Studies on Uranium Mill Tailings.  

National Technical Information Service (NTIS)

Coniferous trees planted in 1974 and deciduous species, that have volunteered since 1970 on uranium mill tailings that had been stabilized to varying degrees using limestone and vegetation, were evaluated. Their survival and growth rates were compared wit...

D. R. Murray M. Turcotte

1982-01-01

419

Crosstalk Noise Estimation for Generic RC Trees  

Microsoft Academic Search

Absrrmr- We propose an estimation method of crosstalk noise for generic RC trees. The proposed method derives an analytic waveform of crosstalk noise in a 2-7r equivalent circuit. The peak voltage is calculated from the closed-form expression, and the crosstalk induced delay is esti- mated using the derived noise waveform. We also develop a transformation method from generic RC trees

Masao Takahashi; Masanori Hashimoto; Hidetoshi Onodera

2001-01-01

420

Fruit trees in a Malaysian rain forest  

Microsoft Academic Search

An inventory was made of 50 ha of primary lowland rain forest in Peninsular Malaysia, in which ca. 340,000 trees 1 cm dbh\\u000a or larger were measured and identified to species. Out of a total plot tree flora of 820 species, 76 species are known to\\u000a bear edible fruit. Especially diverse were the wild species of mango (Mangifera, Anacardiaceae, 12

L. G. Saw; J. V. LaFrankie; K. M. Kochummen; S. K. Yap

1991-01-01

421

Using invariants for phylogenetic tree construction  

Microsoft Academic Search

Phylogenetic invariants are certain polynomials in the joint probability\\u000adistribution of a Markov model on a phylogenetic tree. Such polynomials are of\\u000atheoretical interest in the field of algebraic statistics and they are also of\\u000apractical interest--they can be used to construct phylogenetic trees. This\\u000apaper is a self-contained introduction to the algebraic, statistical, and\\u000acomputational challenges involved in the

Nicholas Eriksson

2007-01-01

422

Exact Bipartite Crossing Minimization under Tree Constraints  

Microsoft Academic Search

A tanglegram consists of a pair of (not necessarily binary) trees T1, T2 with leaf sets L1, L2. Additional edges, called tangles, may connect nodes in L1 with those in L2. The task is to draw the tanglegram with a minimum number of tangle edge crossings while making sure that no crossing occurs between edges within each tree. This problem

Frank Baumann; Christoph Buchheim; Frauke Liers

2010-01-01

423

Hyphomycetes in the snow from gymnosperm trees.  

PubMed

The presence of 26 hyphomycete species was noted in snow water collected from coniferous trees. Camposporium pellucidum, Monodictys peruviana, Polystratorictus fusarioideus, Sporidesmium moniliforme, Tripospermum acerinum and Veronaea botryosa were recorded for the first time to Poland. Among the 26 species found in snow water from coniferous trees predominance of the socalled aero-aquatic hyphomycetes and only a few species belong to the group of aquatic hyphomycetes. PMID:9972045

Czeczuga, B; Or?owska, M

1998-01-01

424

Alcohol co-production from tree crops  

Microsoft Academic Search

A concept for the sustainable production of alcohol from fermentable substrates produced on an annual basis by the reproductive organs (pods, fruits, nuts, berries, etc.) of tree crops is presented. The advantages of tree-crop systems include suitability for use on marginal land, potential productivity equivalent to row crops, minimal maintenance and energy-input requirements, environmental compatibility, and the possibility of co-product

M. Seibert; G. Folger; T. Milne

1982-01-01

425

The generalized Randic index of trees  

Microsoft Academic Search

The Generalised Randic index R??(T) of a tree T is the sum over the edges uv of T of (d(u)d(v))?? where d(x) is the degree of the vertex x in T. For all ? > 0, we find the minimal constantc = ?c(?) such that for all trees on at least 3 vertices R??(T) ? ?c(n + 1) where n

Paul N. Balister; Béla Bollobás; Stefanie Gerke

2007-01-01

426

Parallel object-oriented decision tree system  

DOEpatents

A data mining decision tree system that uncovers patterns, associations, anomalies, and other statistically significant structures in data by reading and displaying data files, extracting relevant features for each of the objects, and using a method of recognizing patterns among the objects based upon object features through a decision tree that reads the data, sorts the data if necessary, determines the best manner to split the data into subsets according to some criterion, and splits the data.

Kamath; Chandrika (Dublin, CA), Cantu-Paz; Erick (Oakland, CA)

2006-02-28

427

Construction of Decision Trees Using Data Cube  

Microsoft Academic Search

Data classification is an important problem in data mining. The traditional classification algorithms based on decision trees\\u000a have been widely used due to their fast model construction and good model understandability. However, the existing decision\\u000a tree algorithms need to recursively partition dataset into subsets according to some splitting criteria i.e. they still have\\u000a to repeatedly compute the records belonging to

Lixin Fu

2005-01-01

428

Tractable Symmetry Breaking Using Restricted Search Trees  

Microsoft Academic Search

We present a new conceptual abstraction in symmetry breaking - the GE-tree. The construction and traversal of a GE-tree breaks all symmetries in any constraint satisfaction or similar prob- lem. We give a polynomial-time algorithm for this construction in the case of CSPs with arbitrary value symmetries. We have implemented this technique, and supply experimental evidence of its practical ef-

Colva M. Roney-dougal; Ian P. Gent; Tom Kelsey; Steve Linton

2004-01-01

429

Bow-tie-tree in EPR cables after accelerated water treeing test  

SciTech Connect

The paper describes the results of accelerated water treeing test after a period of approximately one year with two recently manufactured (1988) varieties of commercial EPR cables, produced by different manufacturers and possessing different cable structures, as well as water impervious XLPE cable for comparison. In the test, bow-tie trees were found in the EPR insulation which was though to develop no or few bow-tie-trees. Examination results of bow-tie-tree in EPR cables are described in this report.

Uematsu, T.; Iwata, Z.; Irie, S.; Fujii, O. (Furukawa Electric Co. Ltd., Tokyo (Japan))

1992-10-01

430

Variable Selection in Classification Trees Based on Imprecise Probabilities  

Microsoft Academic Search

Classiflcation trees are a popular statistical tool with multiple applications. Recent advancements of tra- ditional classiflcation trees, such as the approach of classiflcation trees based on imprecise probabilities by Abellan and Moral (2005), efiectively address their tendency to overfltting. However, another ?aw in- herent in traditional classiflcation trees is not elim- inated by the imprecise probability approach: Due to a

Carolin Strobl

2005-01-01

431

Water treeing and breakdown strength reduction of XLPE insulation  

Microsoft Academic Search

An effort was made to determine factors influencing initiation and growth of vented water trees and to study the reduction of breakdown strength caused by water treeing. Water treeing experiments were performed on both cable samples and Rogowski-type test objects. The influence of aging time and electric field stress was elucidated. In order to test the hypothesis that water treeing

E. Ildstad; J. Sletbak; H. Faremo

1989-01-01

432

The invasiveness of the African Tulip Tree, Spathodea campanulata Beauv  

Microsoft Academic Search

The African Tulip Tree (Spathodea campanulata Beauv.), originally from East and Southern Africa, is a large upright tree with green, pinnately compound leaves and bright orange-coloured flowers. The tree can grow to more than 20m in height and reproduces through seeds and runners. The plant's uses are very limited; it serves as a shade tree or for making fence posts.

Ricardo Labrada; Alejandro Díaz Medina

2009-01-01

433

Growing Greener Cities: A Tree-Planting Handbook.  

ERIC Educational Resources Information Center

This step-by-step guide, developed by the Global ReLeaf organization, presents tree-planting advice and simple steps to organizing a successful community tree-planting and tree-care program. The text is divided into three parts. Part 1 introduces trees and discusses the role they play as components of the living urban environment. Distinctions are…

Moll, Gary; Young, Stanley

434

A Spring Playscape Project: Building a Tree Circle  

ERIC Educational Resources Information Center

The Tree Circle is a green gathering area for children made by planting trees in a circle. For children, the Tree Circle becomes a magical place for dramatic play, quiet retreat, or lively nature exploration. For teachers and parents it becomes a shady grove for snacks and stories. The trees create a sweet spot that changes during the seasons and…

Keeler, Rusty

2009-01-01

435

The Bayesian Additive Classification Tree applied to credit risk modelling  

Microsoft Academic Search

We propose a new nonlinear classification method based on a Bayesian “sum-of-trees” model, the Bayesian Additive Classification Tree (BACT), which extends the Bayesian Additive Regression Tree (BART) method into the classification context. Like BART, the BACT is a Bayesian nonparametric additive model specified by a prior and a likelihood in which the additive components are trees, and it is fitted

Junni L. Zhang; Wolfgang K. Härdle

2010-01-01

436

Predicting Lumber Grade Yields for Standing Hardwood Trees.  

National Technical Information Service (NTIS)

A method was developed for estimating lumber grade yields for hardwood trees using selected tree stem characteristics. The method was tested on sugar maple trees from four National Forests. When tested on trees from the Ottawa National Forest (near the ar...

C. L. Stayton R. M. Marden G. L. Gammon

1971-01-01

437

Rooting a phylogenetic tree with nonreversible substitution models  

Microsoft Academic Search

BACKGROUND: We compared two methods of rooting a phylogenetic tree: the stationary and the nonstationary substitution processes. These methods do not require an outgroup. METHODS: Given a multiple alignment and an unrooted tree, the maximum likelihood estimates of branch lengths and substitution parameters for each associated rooted tree are found; rooted trees are compared using their likelihood values. Site variation

Von Bing Yap; Terry Speed

2005-01-01

438

Computing the Edit-Distance between Unrooted Ordered Trees  

Microsoft Academic Search

An ordered tree is a tree in which each node's incident edges are cyclically ordered; think of the tree as being embedded in the plane. Let A and B be two ordered trees. The edit distance between A and B is the minimum cost of a sequence of operations (contract an edge, uncontract an edge, modify the label of an

Philip N. Klein

1998-01-01

439

Contribution of agroforestry trees to nutrient requirements of intercropped plants  

Microsoft Academic Search

A major tenet of agroforestry, that trees maintain soil fertility, is based primarily on observations of higher crop yields near trees or where trees were previously grown. Recently objective analyses and controlled experiments have addressed this topic. This paper examines the issues of tree prunings containing sufficient nutrients to meet crop demands, the timing of nutrient transfer from decomposition to

C. A. Palm

1995-01-01

440

``Overturned-Stairs'' Adder Trees and Multiplier Design  

Microsoft Academic Search

Wallace trees are the theoretically fastest multioperand adders. However, their complex interconnections do not permit practical implementations. A family of Overturned-Stairs trees which achieve the same speed performance as equivalent Wallace trees in many cases, but require a simple and regular interconnection scheme is introduced. These trees can be designed in a systematic way and laid out regularly in a

Francis Jutand

1992-01-01

441

Comparative water use by dryland trees in Parklands in Senegal  

Microsoft Academic Search

Despite the clear evidence of competition for water between trees and crops, there have been very few studies comparing simultaneous water use by differing tree species in drylands. Comparative water use by dryland trees was measured in Senegal using heat balance gauges at the end of the wet season and in the dry season. Significant differences between tree species were

J. D. Deans; R. C. Munro

2004-01-01

442

Methodology for Computer-Aided Fault Tree Analysis  

Microsoft Academic Search

Fault tree analysis is a systematic, deductive and probabilistic risk assessment tool which elucidates the causal relations leading to a given undesired event. Quantitative fault tree (failure) analysis requires a fault tree and failure data of basic events. Development of a fault tree and subsequent analysis require a great deal of expertise, which may not be available all the time.

R. Ferdous; F. I. Khan; B. Veitch; P. R. Amyotte

2007-01-01

443

A Dynamic Mechanism for Distributed Optimization of Overlay Multicast Tree  

Microsoft Academic Search

To enhance the performance of overlay multicast networks, the overlay multicast tree should be optimized. This optimization prob- lem is a minimum diameter, degree-limited spanning tree (MDDLST) problem which is known to be NP-Hard. We present a new scheme to optimize an overlay multicast tree dynamically. Our algorithm can adapt the tree structure to the dynamic membership and network situation.

Han Choe; Seongho Cho; Chongkwon Kim

2004-01-01

444

The Hydraulic System of Trees: Theoretical Framework and Numerical Simulation  

Microsoft Academic Search

Empirical studies pose the problem of the physiological integration of the tree organism, which is also important on the scale of ecosystems. Recently, spatially distributed models emerged, which approach this problem by reflecting the close linkage between physiological processes and the structures of trees and tree stands. In the case of water flow, the tree organism can be regarded as

THOMAS FRÜH; WINFRIED KURTH

1999-01-01

445

3D FractaL-Tree  

NSDL National Science Digital Library

3D FractaL-Tree allows scientists to collect data from actual specimens in the field or laboratory, insert these measurements into a spatially explicit L-system package, and then visually compare to the computer generated 3D image with such specimens. The measurements are recorded and analyzed in a series of worksheets in Microsoft Excelî and the results are entered into the graphics engine in a Java applet. 3D FractaL-Tree produces a rotatable three-dimensional image of the tree which is helpful for examining such characters as self-avoidance (entanglement and breakage), penetration of sunlight, distances that small herbivores (such as caterpillars) would have to traverse to go from one tip to another, and Voronoi polyhedra of volume distribution of biomass on different subsections of a tree. These and other factors have been discussed in the Adaptive Geometry of Trees (Horn, 1971). Three different representations are available in 3D FractaL-Tree images: wire frame, solid, and transparent. Easy options for saving and exporting images are included.

John Jungck (Beloit College;Biology); Jennifer Spangenberg (Beloit College;Biology); Noppadon Khiripet (National Electronics and Computer Technology Center, Thailand;Bioinformatics Unit); Rawin Viruchpinta (National Electronics and Computer Technology Center, Thailand;); Jutarat Maneewattanapluk (National Electronics and Computer Technology Center, Thailand;)

2007-07-18

446

A study of tea tree oil ototoxicity.  

PubMed

Tea tree oil shows promise as an effective treatment for a number of micro-organisms commonly associated with otitis externa and otitis media, but its possible ototoxicity has not been previously assessed. The ototoxicity of tea tree oil was examined in the guinea pig by measuring the thresholds of the compound auditory nerve action potential (CAP) to tone bursts before and after instillation of the oil into the middle ear. After 30 min of instillation, 100% tea tree oil caused a partial CAP threshold elevation at 20 kHz. A lower concentration of oil [2% tea tree oil dissolved in saline using 0.5% detergent (Tween-80)] did not cause any significant lasting threshold change after middle ear instillation for the same period of time. The latter concentration of oil is greater than the minimum inhibitory concentration reported for most micro-organisms in the effective spectrum of the oil and this suggests that this concentration may be safe and effective provided only short exposures (about 30 min) are used. The results suggest that high concentrations of tea tree oil applied to the round window for a relatively short time are to some extent ototoxic to the high-frequency region of the cochlea. Hence further study is needed to establish whether tea tree oil can be used with safety in the treatment of external and middle ear infections. PMID:10720822

Zhang, S Y; Robertson, D

2000-01-01

447

A natural history of human tree climbing.  

PubMed

Walking and running have dominated the literature on human locomotor evolution at the expense of other behaviors with positive and negative fitness consequences. For example, although modern hunter-gatherers frequently climb trees to obtain important food resources in the canopy, these behaviors are seldom considered within the existing framework of primate positional behavior. As a result, inferences about the arboreal performance capabilities of fossil hominins based on a resemblance to humans may be more complicated than previously assumed. Here we use ethnographic reports of human tree climbing to critically evaluate hypotheses about the performance capabilities of humans in trees compared with other primates. We do so by reviewing the ecological basis of tree climbing behavior among hunter-gatherers and the diversity of human climbing techniques and styles. Results suggest that the biological and adaptive significance of human climbing has been underestimated, and that some humans are surprisingly competent in trees, particularly during vertical climbing and activities in the central core of trees. We conclude that while hominins evolved enhanced terrestrial locomotor performance through time, such shifts may have imposed only minor costs on vertical climbing abilities. The diversity of the locomotor repertoire of modern humans must therefore be taken into account when making form-function inferences during the behavioral reconstruction of fossil hominins. PMID:24630525

Kraft, Thomas S; Venkataraman, Vivek V; Dominy, Nathaniel J

2014-06-01

448

A global history of Australian trees.  

PubMed

Scholars studying the globalization of Australian trees have previously emphasized the rapid natural propagation of Australian trees outside of their native habitats, believing their success to be a reversal of "ecological imperialism" from the "new world" to the "old world." This article argues that the expansion of Australian trees should not be viewed as a biological phenomenon, but as the result of a long-term attempt by powerful states and state-sponsored scientists to select and breed Australian species that could grow in a variety of climates and ecological conditions. Five non-biological factors largely determined the success of these attempts to grow Australian trees: the abundance or paucity of natural forests, state power, the amount of scientific research directed to planting Australian trees, the cost of labor, and the ability to utilize hardwood timbers and bark. This paper compares the use of Australian trees in Australia, India, and South Africa to demonstrate that biology was not the determining factor in the long-term success of many Australian genera and species. PMID:20665086

Bennett, Brett M

2011-01-01

449

Spectra of generalized Bethe trees attached to a path  

Microsoft Academic Search

A generalized Bethe tree is a rooted tree in which vertices at the same distance from the root have the same degree. Let Pm be a path of m vertices. Let {Bi:1?i?m} be a set of generalized Bethe trees. Let Pm{Bi:1?i?m} be the tree obtained from Pm and the trees B1,B2,…,Bm by identifying the root vertex of Bi with the

Oscar Rojo; Luis Medina

2009-01-01

450

A Neural Tree with Partial Incremental Learning Capability  

Microsoft Academic Search

This paper presents a new approach to constructing a neural tree with partial incremental learning capability. The proposed neural tree, called a quadratic-neuron-based neural tree (QUANT), is a tree structured neural network composed of neurons with quadratic neural-type junctions for pattern classification. The proposed QUANT integrates the advantages of decision trees and neural networks. Via a batch-mode training algorithm, the

Mu-Chun Su; Hsu-Hsun Lo

2007-01-01

451

Efficient Exploration of the Space of Reconciled Gene Trees  

PubMed Central

Gene trees record the combination of gene-level events, such as duplication, transfer and loss (DTL), and species-level events, such as speciation and extinction. Gene tree–species tree reconciliation methods model these processes by drawing gene trees into the species tree using a series of gene and species-level events. The reconstruction of gene trees based on sequence alone almost always involves choosing between statistically equivalent or weakly distinguishable relationships that could be much better resolved based on a putative species tree. To exploit this potential for accurate reconstruction of gene trees, the space of reconciled gene trees must be explored according to a joint model of sequence evolution and gene tree–species tree reconciliation. Here we present amalgamated likelihood estimation (ALE), a probabilistic approach to exhaustively explore all reconciled gene trees that can be amalgamated as a combination of clades observed in a sample of gene trees. We implement the ALE approach in the context of a reconciliation model (Szöll?si et al. 2013), which allows for the DTL of genes. We use ALE to efficiently approximate the sum of the joint likelihood over amalgamations and to find the reconciled gene tree that maximizes the joint likelihood among all such trees. We demonstrate using simulations that gene trees reconstructed using the joint likelihood are substantially more accurate than those reconstructed using sequence alone. Using realistic gene tree topologies, branch lengths, and alignment sizes, we demonstrate that ALE produces more accurate gene trees even if the model of sequence evolution is greatly simplified. Finally, examining 1099 gene families from 36 cyanobacterial genomes we find that joint likelihood-based inference results in a striking reduction in apparent phylogenetic discord, with respectively. 24%, 59%, and 46% reductions in the mean numbers of duplications, transfers, and losses per gene family. The open source implementation of ALE is available from https://github.com/ssolo/ALE.git. [amalgamation; gene tree reconciliation; gene tree reconstruction; lateral gene transfer; phylogeny.

Szollosi, Gergely J.; Rosikiewicz, Wojciech; Boussau, Bastien; Tannier, Eric; Daubin, Vincent

2013-01-01

452

Optimised KD-trees for fast image descriptor matching  

Microsoft Academic Search

In this paper, we look at improving the KD-tree for a spe- cific usage: indexing a large number of SIFTand other types of image descriptors. We have extended priority search, to priority search among multiple trees. By creating multiple KD-trees from the same data set and simultaneously search- ing among these trees, we have improved the KD-tree's search performancesignificantly.We have

Chanop Silpa-anan; Richard Hartley

2008-01-01

453

Real-time KD-tree construction on graphics hardware  

Microsoft Academic Search

We present an algorithm for constructing kd-trees on GPUs. This algorithm achieves real-time performance by exploiting the GPU's streaming architecture at all stages of kd-tree construction. Unlike previous parallel kd-tree algorithms, our method builds tree nodes completely in BFS (breadth-first search) order. We also develop a special strategy for large nodes at upper tree levels so as to further exploit

Kun Zhou; Qiming Hou; Rui Wang; Baining Guo

2008-01-01

454

TreeRipper web application: towards a fully automated optical tree recognition software  

PubMed Central

Background Relationships between species, genes and genomes have been printed as trees for over a century. Whilst this may have been the best format for exchanging and sharing phylogenetic hypotheses during the 20th century, the worldwide web now provides faster and automated ways of transferring and sharing phylogenetic knowledge. However, novel software is needed to defrost these published phylogenies for the 21st century. Results TreeRipper is a simple website for the fully-automated recognition of multifurcating phylogenetic trees (http://linnaeus.zoology.gla.ac.uk/~jhughes/treeripper/). The program accepts a range of input image formats (PNG, JPG/JPEG or GIF). The underlying command line c++ program follows a number of cleaning steps to detect lines, remove node labels, patch-up broken lines and corners and detect line edges. The edge contour is then determined to detect the branch length, tip label positions and the topology of the tree. Optical Character Recognition (OCR) is used to convert the tip labels into text with the freely available tesseract-ocr software. 32% of images meeting the prerequisites for TreeRipper were successfully recognised, the largest tree had 115 leaves. Conclusions Despite the diversity of ways phylogenies have been illustrated making the design of a fully automated tree recognition software difficult, TreeRipper is a step towards automating the digitization of past phylogenies. We also provide a dataset of 100 tree images and associated tree files for training and/or benchmarking future software. TreeRipper is an open source project licensed under the GNU General Public Licence v3.

2011-01-01

455

Estimating divergence times in large phylogenetic trees.  

PubMed

A new method, PATHd8, for estimating ultrametric trees from trees with edge (branch) lengths proportional to the number of substitutions is proposed. The method allows for an arbitrary number of reference nodes for time calibration, each defined either as absolute age, minimum age, or maximum age, and the tree need not be fully resolved. The method is based on estimating node ages by mean path lengths from the node to the leaves but correcting for deviations from a molecular clock suggested by reference nodes. As opposed to most existing methods allowing substitution rate variation, the new method smoothes substitution rates locally, rather than simultaneously over the whole tree, thus allowing for analysis of very large trees. The performance of PATHd8 is compared with other frequently used methods for estimating divergence times. In analyses of three separate data sets, PATHd8 gives similar divergence times to other methods, the largest difference being between crown group ages, where unconstrained nodes get younger ages when analyzed with PATHd8. Overall, chronograms obtained from other methods appear smoother, whereas PATHd8 preserves more of the heterogeneity seen in the original edge lengths. Divergence times are most evenly spread over the chronograms obtained from the Bayesian implementation and the clock-based Langley-Fitch method, and these two methods produce very similar ages for most nodes. Evaluations of PATHd8 using simulated data suggest that PATHd8 is slightly less precise compared with penalized likelihood, but it gives more sensible answers for extreme data sets. A clear advantage with PATHd8 is that it is more or less instantaneous even with trees having several thousand leaves, whereas other programs often run into problems when analyzing trees with hundreds of leaves. PATHd8 is implemented in freely available software. PMID:17886144

Britton, Tom; Anderson, Cajsa Lisa; Jacquet, David; Lundqvist, Samuel; Bremer, Kåre

2007-10-01

456

Temperature histories from tree rings and corals  

SciTech Connect

Recent temperature trends in long tree-ring and coral proxy temperature histories are evaluated and compared in an effort to objectively determine how anomalous twentieth century temperature changes have been. These histories mostly reflect regional variations in summer warmth from the tree rings and annual warmth from the corals. In the Northern Hemisphere. the North American tree-ring temperature histories and those from the north Polar Urals, covering the past 1000 or more years, indicate that the twentieth century has been anomalously warm relative to the past. In contrast, the tree-ring history from northern Fennoscandia indicates that summer temperatures during the {open_quote}Medieval Warm Period{close_quote} were probably warmer on average than those than during this century. In the Southern Hemisphere, the tree-ring temperature histories from South America show no indication of recent warming, which is in accordance with local instrumental records. In contrast, the tree-ring, records from Tasmania and New Zealand indicate that the twentieth century has been unusually warm particularly since 1960. The coral temperature histories from the Galapagos Islands and the Great Barrier Reef are in broad agreement with the tree-ring temperature histories in those sectors, with the former showing recent cooling and the latter showing recent warming that may be unprecedented. Overall, the regional temperature histories evaluated here broadly support the larger-scale evidence for anomalous twentieth century warming based on instrumental records. However, this warming cannot be confirmed as an unprecedented event in all regions. 38 refs., 3 figs., 2 tabs.

Cook, E.R. [Tree-Ring Lab., Palisades, NY (United States)

1995-05-01

457

The tree gangs of Glittertown. [Los Angeles organizations promote tree planting  

Microsoft Academic Search

This article describes the activities of four groups in Los Angeles as part of The Global ReLeaf challenge to plant trees for environmental improvement and to combat global warming. The activities include: training of citizen foresters' in selection of tree species, planting sites, maintenance, and fund-raising; education of school children about recycling, organic gardening, water conservation and composting. By working

Boerner-Ein

2009-01-01

458

Tree-Bole Volume Estimation on Standing Pine Trees Using Cascade Correlation Artificial Neural Network Models  

Microsoft Academic Search

Total tree volume estimation is an integral part of forest growth and yield forecasting. Complex formulae are used to estimate bole volume by section, based on relationships proposed by Huber, Smalian and Newton. All these relationships require many measurements of bole diameters at certain heights that are difficult to obtain on standing trees especially when diameter measurements have to be

M. J. Diamantopoulou

2006-01-01

459

Migrating Fault Trees To Decision Trees For Real Time Fault Detection On International Space Station  

Microsoft Academic Search

Fault Tree Analysis shows the possible causes of a system malfunction by enumerating the suspect components and their respective failure modes that may have induced the problem. Complex systems often use fault trees to analyze the faults. Fault diagnosis, when error occurs, is performed by engineers and analysts performing extensive examination of all data gathered during the mission. International Space

Charles Lee; Richard L. Alena; Peter Robinson

2005-01-01

460

Computer-oriented approach to fault-tree construction. [Computer Automated Tree (CAT) code  

Microsoft Academic Search

A methodology for systematically constructing fault trees for general complex systems is developed and applied, via the Computer Automated Tree (CAT) program, to several systems. A means of representing component behavior by decision tables is presented. The method developed allows the modeling of components with various combinations of electrical, fluid and mechanical inputs and outputs. Each component can have multiple

S. L. Salem; G. E. Apostolakis; D. Okrent

1976-01-01

461

Application of fault tree analysis to the service process: service tree analysis approach  

Microsoft Academic Search

Purpose – This study aims to propose a tree-based analytic tool that may be used in analyzing a large-scale and complex service process. The tenet of this tool is based on the Boolean logic and named service tree analysis (STA). The proposed STA aims to reflect the customer participation perspective and to propose how to analyze the service process and

Youngjung Geum; Hyeonju Seol; Sungjoo Lee

2009-01-01

462

Reconfiguration algorithms for tree architectures using sub-tree oriented fault tolerance  

NASA Technical Reports Server (NTRS)

An approach to reconfiguration in tree architectures has been developed in which redundant processors are allocated at the leaves. The scheme is called sub-tree oriented fault tolerances (SOFT) and is capable of tolerating both link failures as well as multiple processor failures. In this paper, the SOFT scheme is examined from the perspective of reconfigurability. Specific algorithms are presented for reconfiguration.

Lowrie, M. B.; Fuchs, W. K.

1986-01-01

463

Up in the Tree - The Overlooked Richness of Bryophytes and Lichens in Tree Crowns  

PubMed Central

Assessing diversity is among the major tasks in ecology and conservation science. In ecological and conservation studies, epiphytic cryptogams are usually sampled up to accessible heights in forests. Thus, their diversity, especially of canopy specialists, likely is underestimated. If the proportion of those species differs among forest types, plot-based diversity assessments are biased and may result in misleading conservation recommendations. We sampled bryophytes and lichens in 30 forest plots of 20 m × 20 m in three German regions, considering all substrates, and including epiphytic litter fall. First, the sampling of epiphytic species was restricted to the lower 2 m of trees and shrubs. Then, on one representative tree per plot, we additionally recorded epiphytic species in the crown, using tree climbing techniques. Per tree, on average 54% of lichen and 20% of bryophyte species were overlooked if the crown was not been included. After sampling all substrates per plot, including the bark of all shrubs and trees, still 38% of the lichen and 4% of the bryophyte species were overlooked if the tree crown of the sampled tree was not included. The number of overlooked lichen species varied strongly among regions. Furthermore, the number of overlooked bryophyte and lichen species per plot was higher in European beech than in coniferous stands and increased with increasing diameter at breast height of the sampled tree. Thus, our results indicate a bias of comparative studies which might have led to misleading conservation recommendations of plot-based diversity assessments.

Boch, Steffen; Muller, Jorg; Prati, Daniel; Blaser, Stefan; Fischer, Markus

2013-01-01

464

Colorado River Droughts Inferred from Tree Rings  

NASA Astrophysics Data System (ADS)

Tree-ring reconstructions for the Colorado River at Lee Ferry, Arizona, have consistently indicated that the modern gaged flow record is unrepresentative of the past few centuries both in the long-term mean annual flow and the severity of extended hydrologic droughts. Information on past droughts can be considered most reliable for the past 500 years, when tree-ring site coverage is relatively dense. Alternative reconstructions using different modeling methods and basic tree-ring data differ in details but are consistent in the timing of periods of relative drought and wetness, and in identifying the late 1500s as the most severe multi-year drought of the last 500 years. Reconstructions for major tributaries emphasize the spatial coherence of droughts and wet periods over the UCRB. The Lee Ferry record of annual flows can be extended back beyond 500 years, with diminished confidence, by analysis of tree rings from dead standing trees and logs. A new reconstruction covering the period A.D. 762-2005 was generated by a series of reconstruction models with time-varying subsets of 11 recently developed tree-ring chronologies from the Upper Colorado River Basin (UCRB) as predictors. The percentage of variance of annual flow at Lee Ferry accounted for by these models decreases from 77 percent after A. D. 1365 to 60 percent before A. D. 1182, as the number of available tree-ring chronologies drops from eleven to three. Correlation analysis and cross-spectral analysis support the hydrologic interpretation of annual as well as decadal fluctuations in the extended reconstruction. The singular multi-decadal event is a drought in the mid-1100s, when the lowest 25- year mean is estimated to be just 84 percent of the modern observed long-term mean. Absence of high flows rather than presence of record-low flows is characteristic of this drought. Results suggest the mid-1100s drought was more severe in the western part of the UCRB than the well-documented North American mega-drought of the late 1500s. Greater site coverage and sample depth (number of trees) are essential to reducing the uncertainty of assessments of hydrologic drought severity in the early part of the tree-ring record.

Meko, D. M.; Woodhouse, C. A.

2007-05-01

465

Factors affecting the concordance between orthologous gene trees and species tree in bacteria  

PubMed Central

Background As originally defined, orthologous genes implied a reflection of the history of the species. In recent years, many studies have examined the concordance between orthologous gene trees and species trees in bacteria. These studies have produced contradictory results that may have been influenced by orthologous gene misidentification and artefactual phylogenetic reconstructions. Here, using a method that allows the detection and exclusion of false positives during identification of orthologous genes, we address the question of whether putative orthologous genes within bacteria really reflect the history of the species. Results We identified a set of 370 orthologous genes from the bacterial order Rhizobiales. Although manifesting strong vertical signal, almost every orthologous gene had a distinct phylogeny, and the most common topology among the orthologous gene trees did not correspond with the best estimate of the species tree. However, each orthologous gene tree shared an average of 70% of its bipartitions with the best estimate of the species tree. Stochastic error related to gene size affected the concordance between the best estimated of the species tree and the orthologous gene trees, although this effect was weak and distributed unevenly among the functional categories. The nodes showing the greatest discordance were those defined by the shortest internal branches in the best estimated of the species tree. Moreover, a clear bias was evident with respect to the function of the orthologous genes, and the degree of divergence among the orthologous genes appeared to be related to their functional classification. Conclusion Orthologous genes do not reflect the history of the species when taken as individual markers, but they do when taken as a whole. Stochastic error affected the concordance of orthologous genes with the species tree, albeit weakly. We conclude that two important biological causes of discordance among orthologous genes are incomplete lineage sorting and functional restriction.

2008-01-01

466

Untangling tanglegrams: comparing trees by their drawings.  

PubMed

A tanglegram is a pair of trees on the same set of leaves with matching leaves in the two trees joined by an edge. Tanglegrams are widely used in biology--to compare evolutionary histories of host and parasite species and to analyze genes of species in the same geographical area. We consider optimization problems in tanglegram drawings. We show a linear time algorithm to decide if a tanglegram admits a planar embedding by a reduction to the planar graph drawing problem. This problem was also studied by Fernau et al. A similar reduction to a graph crossing problem also helps to solve an open problem they posed, showing a fixed-parameter tractable algorithm for minimizing the number of crossings over all d-ary trees. For the case where one tree is fixed, we show an O(n log n) algorithm to determine the drawing of the second tree that minimizes the number of crossings. This improves the bound from earlier methods. We introduce a new optimization criterion using Spearman's footrule distance and give an O(n²) algorithm. We also show integer programming formulations to quickly obtain tanglegram drawings that minimize the two optimization measures discussed. We prove lower bounds on the maximum gap between the optimal solution and the heuristic of Dwyer and Schreiber to minimize crossings. PMID:20530818

Venkatachalam, Balaji; Apple, Jim; St John, Katherine; Gusfield, Dan

2010-01-01

467

LocTree3 prediction of localization.  

PubMed

The prediction of protein sub-cellular localization is an important step toward elucidating protein function. For each query protein sequence, LocTree2 applies machine learning (profile kernel SVM) to predict the native sub-cellular localization in 18 classes for eukaryotes, in six for bacteria and in three for archaea. The method outputs a score that reflects the reliability of each prediction. LocTree2 has performed on par with or better than any other state-of-the-art method. Here, we report the availability of LocTree3 as a public web server. The server includes the machine learning-based LocTree2 and improves over it through the addition of homology-based inference. Assessed on sequence-unique data, LocTree3 reached an 18-state accuracy Q18 = 80 ± 3% for eukaryotes and a six-state accuracy Q6 = 89 ± 4% for bacteria. The server accepts submissions ranging from single protein sequences to entire proteomes. Response time of the unloaded server is about 90 s for a 300-residue eukaryotic protein and a few hours for an entire eukaryotic proteome not considering the generation of the alignments. For over 1000 entirely sequenced organisms, the predictions are directly available as downloads. The web server is available at http://www.rostlab.org/services/loctree3. PMID:24848019

Goldberg, Tatyana; Hecht, Maximilian; Hamp, Tobias; Karl, Timothy; Yachdav, Guy; Ahmed, Nadeem; Altermann, Uwe; Angerer, Philipp; Ansorge, Sonja; Balasz, Kinga; Bernhofer, Michael; Betz, Alexander; Cizmadija, Laura; Do, Kieu Trinh; Gerke, Julia; Greil, Robert; Joerdens, Vadim; Hastreiter, Maximilian; Hembach, Katharina; Herzog, Max; Kalemanov, Maria; Kluge, Michael; Meier, Alice; Nasir, Hassan; Neumaier, Ulrich; Prade, Verena; Reeb, Jonas; Sorokoumov, Aleksandr; Troshani, Ilira; Vorberg, Susann; Waldraff, Sonja; Zierer, Jonas; Nielsen, Henrik; Rost, Burkhard

2014-07-01

468

Parallel search of strongly ordered game trees  

SciTech Connect

The alpha-beta algorithm forms the basis of many programs that search game trees. A number of methods have been designed to improve the utility of the sequential version of this algorithm, especially for use in game-playing programs. These enhancements are based on the observation that alpha beta is most effective when the best move in each position is considered early in the search. Trees that have this so-called strong ordering property are not only of practical importance but possess characteristics that can be exploited in both sequential and parallel environments. This paper draws upon experiences gained during the development of programs which search chess game trees. Over the past decade major enhancements of the alpha beta algorithm have been developed by people building game-playing programs, and many of these methods will be surveyed and compared here. The balance of the paper contains a study of contemporary methods for searching chess game trees in parallel, using an arbitrary number of independent processors. To make efficient use of these processors, one must have a clear understanding of the basic properties of the trees actually traversed when alpha-beta cutoffs occur. This paper provides such insights and concludes with a brief description of a refinement to a standard parallel search algorithm for this problem. 33 references.

Marsland, T.A.; Campbell, M.

1982-12-01

469

UniTree Name Server internals  

SciTech Connect

The UniTree Name Server (UNS) is one of several servers which make up the UniTree storage system. The Name Server is responsible for mapping names to capabilities Names are generally human readable ASCII strings of any length. Capabilities are unique 256-bit identifiers that point to files, directories, or symbolic links. The Name Server implements a UNIX style hierarchical directory structure to facilitate name-to-capability mapping. The principal task of the Name Server is to manage the directories which make up the UniTree directory structure. The principle clients of the Name Server are the FTP Daemon, NFS and a few UniTree utility routines. However, the Name Server is a generalized server and will accept messages from any client. The purpose of this paper is to describe the internal workings of the UniTree Name Server. In cases where it seems appropriate, the motivation for a particular choice of algorithm as description of the algorithm itself will be given.

Mecozzi, D.; Minton, J.

1996-01-01

470

Numerical simulations of dwarf galaxy merger trees  

NASA Astrophysics Data System (ADS)

We investigate the evolution of dwarf galaxies using N-body/smoothed particle hydrodynamics simulations that incorporate their formation histories through merger trees constructed using the extended Press-Schechter formalism. The simulations are computationally cheap and have high spatial resolution. We compare the properties of galaxies with equal final mass but with different merger histories with each other and with those of observed dwarf spheroidals and irregulars. We show that the merger history influences many observable dwarf galaxy properties. We identify two extreme cases that make this influence stand out most clearly: (i) merger trees with one massive progenitor that grows through relatively few mergers and (ii) merger trees with many small progenitors that merge only quite late. At a fixed halo mass, a type (i) tree tends to produce galaxies with larger stellar masses, larger half-light radii, lower central surface brightness and, since fewer potentially angular momentum cancelling mergers are required to build up the final galaxy, a higher specific angular momentum, compared with a type (ii) tree. We do not perform full-fledged cosmological simulations and therefore cannot hope to reproduce all observed properties of dwarf galaxies. However, we show that the simulated dwarfs are similar to real ones.

Cloet-Osselaer, A.; De Rijcke, S.; Vandenbroucke, B.; Schroyen, J.; Koleva, M.; Verbeke, R.

2014-08-01

471

High-performance OCR preclassification trees  

NASA Astrophysics Data System (ADS)

We present an automatic method for constructing high-performance preclassification decision trees for OCR. Good preclassifiers prune the set of alternative classes to many fewer without erroneously pruning the correct class. We build the decision tree using greedy entropy minimization, using pseudo-randomly generated training samples derived from a model of imaging defects, and then `populate' the tree with many more samples to drive down the error rate. In [BM94] we presented a statistically rigorous stopping rule for population that enforces a user-specified upper bound on error: this works in practice, but is too conservative, driving the error far below the bound. Here, we describe a refinement that achieves the user- specified accuracy more closely and thus improves the pruning rate of the resulting tree. The method exploits the structure of the tree: the essential technical device is a leaf-selection rule based on Good's Theorem [Good53]. We illustrate its effectiveness through experiments on a pan-European polyfont classifier.

Baird, Henry S.; Mallows, C. L.

1995-03-01

472

Phylogenetic tree shapes resolve disease transmission patterns  

PubMed Central

Background and Objectives: Whole-genome sequencing is becoming popular as a tool for understanding outbreaks of communicable diseases, with phylogenetic trees being used to identify individual transmission events or to characterize outbreak-level overall transmission dynamics. Existing methods to infer transmission dynamics from sequence data rely on well-characterized infectious periods, epidemiological and clinical metadata which may not always be available, and typically require computationally intensive analysis focusing on the branch lengths in phylogenetic trees. We sought to determine whether the topological structures of phylogenetic trees contain signatures of the transmission patterns underlying an outbreak. Methodology: We use simulated outbreaks to train and then test computational classifiers. We test the method on data from two real-world outbreaks. Results: We show that different transmission patterns result in quantitatively different phylogenetic tree shapes. We describe topological features that summarize a phylogeny’s structure and find that computational classifiers based on these are capable of predicting an outbreak’s transmission dynamics. The method is robust to variations in the transmission parameters and network types, and recapitulates known epidemiology of previously characterized real-world outbreaks. Conclusions and implications: There are simple structural properties of phylogenetic trees which, when combined, can distinguish communicable disease outbreaks with a super-spreader, homogeneous transmission and chains of transmission. This is possible using genome data alone, and can be done during an outbreak. We discuss the implications for management of outbreaks.

Colijn, Caroline; Gardy, Jennifer

2014-01-01

473

The tree tenure factor in agroforestry with particular reference to Africa  

Microsoft Academic Search

Rights over trees are often distinct from rights over land. Tree tenure consists of a bundle of rights over trees and their produce which may be held by different people at different times. These rights include the right to own or inherit trees, the right to plant trees, the right to use trees and tree products, the right to dispose

Louise Fortmann

1985-01-01

474

Efficient exploration of the space of reconciled gene trees.  

PubMed

Gene trees record the combination of gene-level events, such as duplication, transfer and loss (DTL), and species-level events, such as speciation and extinction. Gene tree-species tree reconciliation methods model these processes by drawing gene trees into the species tree using a series of gene and species-level events. The reconstruction of gene trees based on sequence alone almost always involves choosing between statistically equivalent or weakly distinguishable relationships that could be much better resolved based on a putative species tree. To exploit this potential for accurate reconstruction of gene trees, the space of reconciled gene trees must be explored according to a joint model of sequence evolution and gene tree-species tree reconciliation. Here we present amalgamated likelihood estimation (ALE), a probabilistic approach to exhaustively explore all reconciled gene trees that can be amalgamated as a combination of clades observed in a sample of gene trees. We implement the ALE approach in the context of a reconciliation model (Szöll?si et al. 2013), which allows for the DTL of genes. We use ALE to efficiently approximate the sum of the joint likelihood over amalgamations and to find the reconciled gene tree that maximizes the joint likelihood among all such trees. We demonstrate using simulations that gene trees reconstructed using the joint likelihood are substantially more accurate than those reconstructed using sequence alone. Using realistic gene tree topologies, branch lengths, and alignment sizes, we demonstrate that ALE produces more accurate gene trees even if the model of sequence evolution is greatly simplified. Finally, examining 1099 gene families from 36 cyanobacterial genomes we find that joint likelihood-based inference results in a striking reduction in apparent phylogenetic discord, with respectively. 24%, 59%, and 46% reductions in the mean numbers of duplications, transfers, and losses per gene family. The open source implementation of ALE is available from https://github.com/ssolo/ALE.git. PMID:23925510

Szöllõsi, Gergely J; Rosikiewicz, Wojciech; Boussau, Bastien; Tannier, Eric; Daubin, Vincent

2013-11-01

475

Scattering measurements on natural and model trees  

NASA Technical Reports Server (NTRS)

The acoustical back scattering from a simple scale model of a tree has been experimentally measured. The model consisted of a trunk and six limbs, each with 4 branches; no foliage or twigs were included. The data from the anechoic chamber measurements were then mathematically combined to construct the effective back scattering from groups of trees. Also, initial measurements have been conducted out-of-doors on a single tree in an open field in order to characterize its acoustic scattering as a function of azimuth angle. These measurements were performed in the spring, prior to leaf development. The data support a statistical model of forest scattering; the scattered signal spectrum is highly irregular but with a remarkable general resemblance to the incident signal spectrum. Also, the scattered signal's spectra showed little dependence upon scattering angle.

Rogers, James C.; Lee, Sung M.

1990-01-01

476

Competitive neural trees for pattern classification.  

PubMed

This paper presents competitive neural trees (CNeT's) for pattern classification. The CNeT contains m-ary nodes and grows during learning by using inheritance to initialize new nodes. At the node level, the CNeT employs unsupervised competitive learning. The CNeT performs hierarchical clustering of the feature vectors presented to it as examples, while its growth is controlled by forward pruning. Because of the tree structure, the prototype in the CNeT close to any example can be determined by searching only a fraction of the tree. This paper introduces different search methods for the CNeT, which are utilized for training as well as for recall. The CNeT is evaluated and compared with existing classifiers on a variety of pattern classification problems. PMID:18255815

Behnke, S; Karayiannis, N B

1998-01-01

477

Minimum spanning trees for community detection  

NASA Astrophysics Data System (ADS)

A simple deterministic algorithm for community detection is provided by using two rounds of minimum spanning trees. By comparing the first round minimum spanning tree (1st-MST) with the second round spanning tree (2nd-MST) of the network, communities are detected and their overlapping nodes are also identified. To generate the two MSTs, a distance matrix is defined and computed from the adjacent matrix of the network. Compared with the resistance matrix or the communicability matrix used in community detection in the literature, the proposed distance matrix is very simple in computation. The proposed algorithm is tested on real world social networks, graphs which are failed by the modularity maximization, and the LFR benchmark graphs for community detection.

Wu, Jianshe; Li, Xiaoxiao; Jiao, Licheng; Wang, Xiaohua; Sun, Bo

2013-05-01

478

Parameter identification in multinomial processing tree models.  

PubMed

Multinomial processing tree models form a popular class of statistical models for categorical data that have applications in various areas of psychological research. As in all statistical models, establishing which parameters are identified is necessary for model inference and selection on the basis of the likelihood function, and for the interpretation of the results. The required calculations to establish global identification can become intractable in complex models. We show how to establish local identification in multinomial processing tree models, based on formal methods independently proposed by Catchpole and Morgan (1997) and by Bekker, Merckens, and Wansbeek (1994). This approach is illustrated with multinomial processing tree models for the source-monitoring paradigm in memory research. PMID:20805606

Schmittmann, Verena D; Dolan, Conor V; Raijmakers, Maartje E J; Batchelder, William H

2010-08-01

479

Tree attenuation at 20 GHz: Foliage effects  

NASA Technical Reports Server (NTRS)

Static tree attenuation measurements at 20 GHz (K-Band) on a 30 deg slant path through a mature Pecan tree with and without leaves showed median fades exceeding approximately 23 dB and 7 dB, respectively. The corresponding 1% probability fades were 43 dB and 25 dB. Previous 1.6 GHz (L-Band) measurements for the bare tree case showed fades larger than those at K-Band by 3.4 dB for the median and smaller by approximately 7 dB at the 1% probability. While the presence of foliage had only a small effect on fading at L-Band (approximately 1 dB additional for the median to 1% probability range), the attenuation increase was significant at K-Band, where it increased by about 17 dB over the same probability range.

Vogel, Wolfhard J.; Goldhirsh, Julius

1993-01-01

480

The inverse problem for certain tree parameters  

PubMed Central

Let p be a graph parameter that assigns a positive integer value to every graph. The inverse problem for p asks for a graph within a prescribed class (here, we will only be concerned with trees), given the value of p. In this context, it is of interest to know whether such a graph can be found for all or at least almost all integer values of p. We will provide a very general setting for this type of problem over the set of all trees, describe some simple examples and finally consider the interesting parameter “number of subtrees”, where the problem can be reduced to some number-theoretic considerations. Specifically, we will prove that every positive integer, with only 34 exceptions, is the number of subtrees of some tree.

Czabarka, Eva; Szekely, Laszlo; Wagner, Stephan

2009-01-01