These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

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. PMID:22545205

Lu, Rong; Miyakoshi, Tetsuo

2012-01-01

2

Seasonal Conductivity and Embolism in the Roots and Stems of Two Clonal Ring-Porous Trees, Sassafras albidum (Lauraceae) and Rhus typhina (Anacardiaceae)  

Microsoft Academic Search

Seasonal xylem (wood) conductivity and embolism (air blockage) patterns were monitored in roots vs. stems of two clonal ring- porous tree species, Sassafras albidum and Rhus typhina, throughout 1996 and 1997. Stems of both species were 100% embolized in the early spring and became conductive by late June following leaf expansion and maturation of new earlywood vessels. Dyes indicated the

Laura L. Jaquish; Frank W. Ewers

2001-01-01

3

Eosinophilic Gastroenteritis Due to Rhus Ingestion Presenting with Gastrointestinal Hemorrhage  

PubMed Central

Rhus-related illnesses in Korea are mostly caused by ingestion of parts of the Rhus tree. Contact dermatitis occurrence after ingestion of Rhus-related food is very common in Korea. However, Rhus-related gastrointestinal disease is very rare. Herein, we present a case of eosinophilic gastroenteritis caused by Rhus ingestion. A 75-year-old woman was admitted with hematemesis and hematochezia after Rhus extract ingestion. Routine laboratory tests revealed leukocytosis without eosinophilia. Endoscopy showed friable and granular mucosal changes with touch bleeding in the second portion of the duodenum. Abdominal computed tomography revealed edematous wall thickening of the duodenum and proximal jejunal loops. Patch testing with Rhus extracts showed a strong positive reaction, suggesting Rhus as the allergen. Her symptoms improved after avoidance of the allergen.

Choi, Wonsuk; Choi, Chan; Cho, Kyuman; Park, Chang-Hwan; Kim, Hyun-Soo; Choi, Sung-Kyu; Rew, Jong-Sun

2015-01-01

4

Seasonal conductivity and embolism in the roots and stems of two clonal ring-porous trees, Sassafras albidum (Lauraceae) and Rhus typhina (Anacardiaceae).  

PubMed

Seasonal xylem (wood) conductivity and embolism (air blockage) patterns were monitored in roots vs. stems of two clonal ring-porous tree species, Sassafras albidum and Rhus typhina, throughout 1996 and 1997. Stems of both species were 100% embolized in the early spring and became conductive by late June following leaf expansion and maturation of new earlywood vessels. Dyes indicated the stem conduction was restricted almost exclusively to the current year's growth ring. Stems became totally embolized again by early October, before the first freezing temperatures. In contrast, woody roots of both species maintained low embolism values, many conductive growth rings, and high conductivity values regardless of the season. No positive root pressures were detected in either species. The mean frost depth (204 ± 11 mm) was deeper than all sampled roots of Rhus and 47% of sampled roots of Sassafras. The roots that had been in frozen soil either avoided embolism altogether or they were able to reverse embolism by a mechanism other than positive root pressures. PMID:11222243

Jaquish, L L; Ewers, F W

2001-02-01

5

Amorolfine vs. ciclopirox – lacquers for the treatment of onychomycosis  

PubMed Central

Amorolfine 5% and ciclopirox 8% nail lacquers are commonly used in topical treatment of onychomycosis. These formulations may be used alone or in combination with oral antifungal agents. Amorolfine and ciclopirox are valuable therapeutic options, however, their usage in monotherapy should be limited. Proper amorolfine and ciclopirox penetration through the nail plate is provided by transungual drug delivery systems. Although amorolfine and ciclopirox have a different mode of action, they both exhibit a broad antifungal activity. The use of antifungal nail lacquers in combination with oral agents, such as terbinafine and itraconazole, improves efficacy of antifungal therapy.

Szewczyk, Anna E.; Bienias, Wojciech; Wojciechowska, Agnieszka; Pastuszka, Marta; Oszukowska, Magdalena; Kaszuba, Andrzej

2015-01-01

6

[Sumac (Rhus chinensis Mill) biomass refinery engineering].  

PubMed

Sumac (Rhus chinensis Mill) is an abundant and widely distributed Chinese native plant. Sumac fruit contains low content of vegetable oil, as an atypical oil plants hardly being processed through traditional vegetable oil production technologies. Based on our own studies on the characteristics of sumac fruit and branches, we established a novel model of sumac biomass refinery, and constructed the sumac biomass refinery technology system and eco-industrial chain integration. Steam explosion was the key technology, and several components fractionation technologies were integrated in the sumac biomass refinery system. The fractionated components were converted into different products depending on their functional features. Eight products including sumac fruit oil, biodiesel, protein feed, flavonoids, unbleached facial tissue, phenolic resin, biomass briquette and biogas were produced in the refinery. The extracted sumac fruit oil by steam explosion pretreatment was applied for the new food resource of Ministry of Health, and the permit was approved. This research provides a new model for the development of atypical wild plant resources. PMID:25118393

Wang, Lan; Wang, Ning; Li, Tan; Chen, Hongzhang

2014-05-01

7

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

8

Biological Activities of Extracts from Sumac ( Rhus spp.): A Review  

Microsoft Academic Search

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\\u000a and tropical regions worldwide, often grow in areas of marginal agricultural capacity, and have a long history of use by indigenous\\u000a people for medicinal and other uses. The research efforts on sumac

Sierra Rayne; G. Mazza

2007-01-01

9

Antimutagenic activity of flavonoids from the heartwood of Rhus verniciflua.  

PubMed

Pretreatment of the methanolic extract of the heartwood of Rhus verniciflua (Anacardiaceae) to rats prevented the activation of hepatic microsomal cytochrome p(450) enzymes, inhibition of hepatic glutathione S-transferase by bromobenzene treatment, respectively, and therefore significantly decreased malondialdehyde content in the rat. The Ames test showed that the addition of 1.0 mg/plate of the methanolic extract or the EtOAc fraction of the Rhus verniciflua heartwood extract potentially inhibited the mutagenicity by aflatoxin B(1). Column chromatography of the EtOAc fraction yielded four flavonoids, garbanzol (1), sulfuretin (2), fisetin (3), fustin (4), mollisacasidin (5). When these components were subjected to the Ames test, it was found that sulfuretin might effectively prevent the metabolic activation or scavenge electrophilic intermediates capable of causing mutation. In contrast, fustin showed a dose-independent antimutagenic activity and it has mutagenic/antimutagenic activity. However, a mixture of sulfuretin and fustin (1:1) exhibited dose-dependent antimutagenicity indicating that sulfuretin inhibited the mutagenicity of fustin. These results suggest that the extract of Rhus verniciflua heartwood containing flavonoid complex could be a potent anticarcinogen. PMID:14698512

Park, Kun-Young; Jung, Geun-Ok; Lee, Kyung-Tae; Choi, Jongwon; Choi, Moo-Young; Kim, Gab-Tae; Jung, Hyun-Ju; Park, Hee-Juhn

2004-01-01

10

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

11

Tailoring Thin Film-Lacquer Coatings for Space Applications  

NASA Technical Reports Server (NTRS)

Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's then-nal control requirements, there is often a need for a variation of solar absorptance (alpha(sub s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of alpha(sub s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

1998-01-01

12

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. PMID:22262932

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

2011-01-01

13

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

14

Comparative physiology of burned and unburned Rhus laurina after chaparral wildfire  

Microsoft Academic Search

Laurel Sumac (Rhus laurina) is a dominant member of the coastal chaparral community of southern California that survives periodic burning by wildfires by resprouting from a lignotuber (root crown). We investigated the physiological basis for resprouting by comparing shoot elongation, leaf nitrogen content, tissue water status, leaf conductance to water vapor diffusion, and photosynthetic rates of post-fire R. laurina to

J. DeSouza; P. A. Silka; S. D. Davis

1986-01-01

15

Corrosion behavior of lacquered tinplate cans in contact with cockles (cardium edulis) in brine solution  

SciTech Connect

Tinplate cans internally coated with an epoxyphenolic plus zinc oxide (ZnO) lacquer were studied. The relationship between lacquer adhesion and total chromium, metallic chromium, and chromium oxide (CrO{sub x}) in the passivated layer was analyzed. The thickness of the CrO{sub x} layer is a controlling parameter of adhesion. Electrochemical impedance spectroscopy (EIS), direct current (DC) polarization, and atomic absorption (AA) experiments were conducted at different time periods up to 150 days. EIS, DC, and AA results indicated that the passivation treatment with the lowest chromium content (Type 1) showed slightly worse corrosion behavior, with substantial iron dissolution and sulfur staining of the tinplate, than passivation treatments Types 2 and 3, which behaved similarly to each other. A fully opened can was used as the working electrode and electrolytic cell in contact with canned cockles (a mollusc, Cardium edulis).

Bastidas, J.M.; Cabanes, J.M.; Catala, R.

2000-04-01

16

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. PMID:23131104

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

2013-01-01

17

Trees  

NSDL National Science Digital Library

This tutorial covers various aspects of trees. It explains which chemicals cause leaves to change colors, how the process of photosynthesis works, the functions of bark, roots, pollen and leaves, and the effect of trees on nearby temperature.

18

Assay of topical corticosteroids. Efficacy of suppression of experimental Rhus dermatitis in humans.  

PubMed

Rhus dermatitis, experimentally induced in humans, was used as a model for determining the efficacy of various proprietary topical steroids. One-centimeter squares of vesicular dermatitis were induced by patch application of Rhus oleoresin. The steroids were then applied without occlusion once daily for four days, with readings of the therapeutic effect taken on the fifth day. Only potent steroids provided unequivocal suppression in this severe test. The rank order of efficacy corresponded to clinical experience. Cream and ointment formulations of the same steroid at the same strength did not differ. High strength preparations were more effective than regular strengths. Relief of pruritus was an important early effect of efficaceous steroids. PMID:133636

Kaidbey, K H; Kligman, A M

1976-06-01

19

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. PMID:25024508

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

2014-01-01

20

[Investigation on comparison method of chromatographic fingerprints of lacquer coat of cars and its application].  

PubMed

The comparison method of fingerprints of the lacquer coat of cars (LCC) was established by using thermal desorption instrument with gas chromatography. The actual LCC samples were also analyzed. The samples were cut out to proper size and placed in the desorption furnace of the thermal desorption instrument. The volatile organic compounds in LCC were desorbed from the lacquer coat samples in the furnace under the chosen temperature, then separated in the capillary column and detected on a flame ionization detector of gas chromatography. The incipient judgment whether the two fingerprints of LCC were the same can be made from the contour and figure of the chromatograms. To make farther study of the two similar fingerprints, the overlap ratio of the peaks and relative retention values were given in the article. The two LCC samples can be regarded as the same if the overlap ratio of peaks was more than 90%, and the similarity of the ratio of relative retention times r(t2) and r(t1) and relative peak areas r(A2) and r(A1) in the two fingerprints were more than 99% and 70%, respectively. The method is good in repeatability and is easily carried out. The peaks in the fingerprint can be readily recognized. The fingerprint was characterized quantitatively. The method can be used in the department of traffic police and the comparison result can be used as material evidence in the court. PMID:16499002

Li, Chen; Liang, Bing; Shi, Yanping; Jiang, Shengxiang; Ou, Qingyu

2005-11-01

21

Lacquer poisoning  

MedlinePLUS

... control or a health care professional. If the chemical was swallowed, immediately give the person water, unless instructed otherwise by a health care provider. If the person breathed in the poison, immediately move him or her to fresh air.

22

Anti-platelet effects of bioactive compounds isolated from the bark of Rhus verniciflua Stokes.  

PubMed

It has previously been shown that EtOAc extracts of Rhus verniciflua Stokes (RVS) inhibit the platelet aggregation response. In this report, bioassay-guided fractionation using ADP-, arachidonic acid-, and collagen-induced human platelet aggregation by a whole blood aggregometer yielded the bioactive compounds isomaltol and pentagalloyl glucose from different highly effective fractions. In addition, column chromatography of fractions from RVS yielded another five compounds: butin, fisetin, sulfuretin, butein and 3,4',7,8-tetrahydroxyflavone. We investigated the effects of bioactive compounds from RVS fractions on several markers of platelet activation using receptor expression on platelet membranes, including glycoprotein IIb/IIIa (CD41), GPIIb/IIIa-like expression (PAC-1) and P-selectin (CD62), and intracelluar calcium mobilization responses by flow cytometry in healthy subjects. Dose-dependent inhibition of platelet aggregation and significantly decreased platelet activation were observed for the isomaltol- and pentagalloyl glucose-treated platelets, respectively. These results show that isomaltol and pentagalloyl glucose from the bark of Rhus verniciflua Stokes have potent anti-platelet activity and emphasize the need to further examine the mechanism of these active compounds for platelet modulation. PMID:16431050

Jeon, Won Kyung; Lee, Ju Hyun; Kim, Ho Kyoung; Lee, A Yeong; Lee, Sung Ok; Kim, Young Sup; Ryu, Shi Yong; Kim, Soo Young; Lee, Yong Jin; Ko, Byoung Seob

2006-06-15

23

Antirheumatoid arthritis effect of Rhus verniciflua and of the active component, sulfuretin.  

PubMed

Oral administration of the MeOH extract of Rhus verniciflua or of an EtOAc fraction containing an EtOAc-soluble portion of the MeOH extract slightly decreased rheumatoid arthritis (RA) and C-reactive protein (CRP) factors in Freund's complete adjuvant reagent FCA-treated rats, indicating that they are active extracts for rheumatoid arthritis, the EtOAc extract being more active. Treatment with these two extracts prevented histological changes such as synovial cell proliferation, inflammatory cell infiltration and fat necrosis compared with an FCA-treated group. Oral administration (30 mg/kg) of sulfuretin and fustin, which were isolated from the EtOAc extract by activity-guided separation, significantly decreased RA and CRP factors, the former being more active than the latter. Treatment with the EtOAc fraction ( p. o.) containing sulfuretin significantly decreased malondialdehyde (MDA) formation, and highly increased the activities of superoxide dismutase, catalase and glutathione peroxidase. Inhibition of xanthine oxidase and aldehyde oxidase in FCA-treated rats was also evident. Since treatment with sulfuretin and the EtOAc extract decreased the concentration of infiltrated mast cells in the rat knee exhibiting rheumatoid arthritis, we suggest that the Rhus verniciflua extract, which contains sulfuretin as an active component, may prevent rheumatoid syndromes by inhibiting reactive oxygen species. PMID:14648391

Choi, Jongwon; Yoon, Byung-Jae; Han, Yong Nam; Lee, Kyung-Tae; Ha, Joohun; Jung, Hyun-Ju; Park, Hee-Juhn

2003-10-01

24

Exposure to airborne particles and volatile organic compounds from polyurethane molding, spray painting, lacquering, and gluing in a workshop.  

PubMed

Due to the health risk related to occupational air pollution exposure, we assessed concentrations and identified sources of particles and volatile organic compounds (VOCs) in a handcraft workshop producing fishing lures. The work processes in the site included polyurethane molding, spray painting, lacquering, and gluing. We measured total VOC (TVOC) concentrations and particle size distributions at three locations representing the various phases of the manufacturing and assembly process. The mean working-hour TVOC concentrations in three locations studied were 41, 37, and 24 ppm according to photo-ionization detector measurements. The mean working-hour particle number concentration varied between locations from 3000 to 36,000 cm-3. Analysis of temporal and spatial variations of TVOC concentrations revealed that there were at least four substantial VOC sources: spray gluing, mold-release agent spraying, continuous evaporation from various lacquer and paint containers, and either spray painting or lacquering (probably both). The mold-release agent spray was indirectly also a major source of ultrafine particles. The workers' exposure can be reduced by improving the local exhaust ventilation at the known sources and by increasing the ventilation rate in the area with the continuous source. PMID:25849539

Mølgaard, Bjarke; Viitanen, Anna-Kaisa; Kangas, Anneli; Huhtiniemi, Marika; Larsen, Søren Thor; Vanhala, Esa; Hussein, Tareq; Boor, Brandon E; Hämeri, Kaarle; Koivisto, Antti Joonas

2015-01-01

25

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

26

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. 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

27

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

28

Correlation between antibutyrylcholinesterasic and antioxidant activities of three aqueous extracts from Tunisian Rhus pentaphyllum  

PubMed Central

For centuries, plants have been used in traditional medicines and there has been recent interest in the chemopreventive properties of compounds derived from plants. In the present study, we investigated the antibutyrylcholinestrasic (anti-BuChE) and antioxidant (against some free radicals) activities of extracts from Rhus pentaphyllum. Aqueous extracts were prepared from powdered R. pentaphyllum roots, leaves and seeds and characterized for the presence of tannins, flavonoids and coumarins. Seeds aqueous extract contained the highest quantities of both flavonoids and tannins (21.12% and 17.45% respectively). In the same way, seeds extracts displayed remarkable inhibition against BuChE over 95%, at 100 ?g/ml and with IC50 0.74 ?g/ml. In addition, compared to leaves and roots extracts, seeds aqueous extract revealed relatively strong antiradical activity towards the ABTS.+ (IC50 = 0.25 ?g/ml) and DPPH (IC50 = 2.71 ?g/ml) free radicals and decreased significantly the reactive oxygen species such O2.- (IC50 = 2.9 ?g/ml) formation evaluated by the non-enzymatic generating O2.- system (Nitroblue tetrazolium/riboflavine). These data suggest that the anti-BuChE activities mechanism of these extracts occurs through a free radical scavenging capacities. The present study indicates that extracts of Rhus pentaphyllum leaves, seeds and roots are a significant source of compounds, such as tannins, flavonoids and coumarins, with anti-BuChE and antioxidant activities, and thus may be useful for chemoprevention. PMID:21880140

2011-01-01

29

Trees, Trees, Trees!  

NSDL National Science Digital Library

In these activities, students increase their awareness and knowledge of trees through research, literature and hands-on contact. The students will adopt and identify a tree of their choice, make a rubbing of the bark, draw a picture, and research about their tree. They will also write an original piece about their tree, document how it changes throughout the year, and learn the difference between deciduous and coniferous trees.

1998-01-01

30

Ozone exposure-response curves for tree species in Great Smoky Mountains National Park: A re-evaluation of how potential impacts may have changed over the past 25 years  

EPA Science Inventory

Seedlings of tree species native to Great Smoky Mountains National Park were exposed to ozone in open-top chambers for one or two growing seasons. Species used were red maple (Acer rubrum), chestnut oak (Quercus prinus), black locust (Robinia pseudoacadia), winged sumac (Rhus co...

31

Extract of Rhus verniciflua Bark Suppresses 2,4-Dinitrofluorobenzene-Induced Allergic Contact Dermatitis  

PubMed Central

Rhus verniciflua Stokes (RV) has traditionally been used as a food supplement and a traditional herbal medicine for centuries in Korea. Recent studies suggest that RV has potent antioxidative, antitumor, and anti-inflammatory properties. In this study, the anti-inflammatory effects of RV from mice sensitized with 2,4-dinitrofluorobenzene (DNFB) and activated macrophages were investigated. The results showed that RV reduced ear swelling and hyperplasia of ear tissue as well as an increase in vascular permeability, which are characteristics of allergic contact dermatitis (ACD) with evident histomorphological changes in epidermis and dermis. Decreased numbers of infiltrated mast cells were seen in RV extract treated group, using toluidine blue staining. RV extract significantly regulates the expression of inducible nitric oxide synthase (iNOS) at the translational level in activated macrophages. Furthermore, RV extract and its active compound, fisetin, attenuated the level of tumor necrosis factor-? (TNF-?) and interleukin 6 (IL-6) mRNA in LPS-stimulated macrophages. Anti-ACD effect of RV extract may be due to the suppression of iNOS and proinflammatory cytokines which might be mediated via the NF?B signaling pathways. Collectively, RV extract has potential for alleviating ACD-like symptoms induced by DNFB in the mouse. PMID:23710240

Park, Dong Ki; Lee, Yang Gi; Park, Hye-Jin

2013-01-01

32

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

2014-01-01

33

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. PMID:24223060

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

2013-01-01

34

Effect of sumach (Rhus coriaria L.) extracts on the oxidative stability of peanut oil.  

PubMed

The antioxidant activities of sumach (Rhus coriaria L.) extracts and butylated hydroxyanisole (BHA) at various concentrations were tested in natural peanut oil stored at 65 degrees C for 35 days. The concentrations (weight/volume) of extracts added into oil were 1.0%, 3.0%, and 5.0%, and those of BHA were 0.1%, 0.3%, and 0.5%. Antioxidant effect was determined by the measurement of peroxide value. After 7 days of storage, BHA and extracts of sumach were active in varying degrees against autoxidation of peanut oil, compared with the control test (P <.01). The sumach extracts generally inhibited the formation of hydroperoxide, as did BHA. After 28 days of storage, antioxidant effects of extracts were significantly decreased when compared with BHA. The decrease in the antioxidant activity of extracts might have resulted from the decrease of polyphenolic constituents. The results showed that high concentrations can enhance the potency of the antioxidant effect of sumach extract. PMID:12804022

Ozcan, Musa

2003-01-01

35

Extract from Rhus verniciflua Stokes is capable of inhibiting the growth of human lymphoma cells.  

PubMed

Rhus verniciflua Stokes (RVS), used as a food additive and a traditional herbal medicine, has both antioxidant and antitumor activities which are known to be closely associated with the polyphenolic compounds that it contains. In the present study, we purified a fraction from a crude acetone extract of RVS, named RCMF (RVS chloroform-methanol fraction), and evaluated its ability to scavenge free radicals and inhibit cell growth. In addition, the active compounds responsible for the activities were identified. Results showed that RCMF contained an antioxidant potential and strongly suppressed the proliferative capability of B lymphoma cells. RCMF-mediated suppression of cell growth was verified to be apoptotic, based on the increased DNA fragmentation and low fluorescence intensity in the nuclei after propidium iodide staining, and also on the appearance of DNA laddering. Finally, EI-MS, 1H-NMR, and 13C-NMR spectra confirmed that RCMF contained flavonoid derivatives, including protocatechuic acid, fustin, fisetin, sulfuretin, and butein, suggesting that these flavonoid derivatives are the main active compounds responsible for the antioxidant and antiproliferative activities of RCMF. PMID:15234068

Lee, J-C; Lee, K-Y; Kim, J; Na, C-S; Jung, N-C; Chung, G-H; Jang, Y-S

2004-09-01

36

Identification of Rhus verniciflua Stokes compounds that exhibit free radical scavenging and anti-apoptotic properties.  

PubMed

Rhus verniciflua Stokes (RVS) is a widely used herbal plant with various biological properties. Our previous study using cultured neuronal cells showed that an ethanol extract of RVS had strong antioxidant properties. In this study, we characterized the antioxidant activity of the RVS ethanol extract and identified the active compounds responsible for this activity. From the RVS ethanol extract, we derived three water-eluted fractions and another three fractions eluted by organic solvents, and determined that the water-eluted fractions are what protect against reactive oxygen species (ROS) generated by iron and enzymes. Water-eluted fraction F(2) was the most efficient antioxidant. Moreover, DNA fragmentation and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining experiments revealed that F(2) also protects against thymocyte apoptosis mediated by hydroxyl radicals. Finally, EI-MS, (1)H-NMR, and (13)C-NMR spectra signals confirmed that the fraction contained flavonoid derivatives, including fustin, quercetin, butein, and sulfuretin. These results suggest that the flavonoid derivatives in F(2) are the compounds in the RVS ethanol extract that act as antioxidants. PMID:12020808

Lee, Jeong-Chae; Lim, Kye-Taek; Jang, Yong-Suk

2002-04-15

37

Inhibitory effect of the compounds isolated from Rhus verniciflua on aldose reductase and advanced glycation endproducts.  

PubMed

The aim of this paper was to evaluate active principles for diabetic complications from Rhus verniciflua. Nine compounds were isolated via bioactivity guided fractionation and isolation and tested for their effects on recombinant human aldose reductase and advanced glycation endproducts. Butein and sulfuretin isolated from ethyl acetate fraction were found to possess strongly both forms of aldose reductase and advanced glycation endproducts inhibition. The inhibitory activity of butein against a recombinant human aldose reductase (IC(50) value: 0.5 microM) was 2.6 times more potent that of epalrestat as a positive control (IC(50) value: 1.3 microM). The inhibitory potency of sulfuretin (IC(50) value: 124.7 microM) on advanced glycation end-products was about 10 times more potent that of aminoguanidine as a positive control (IC(50) value: 1231.0 microM). These compounds all displayed antioxidative activity which was measured by Photochem apparatus. It was concluded, therefore, butein and sulfuretin have antioxidative as well as aldose reductase and advanced glycation endproducts inhibitory effects. As a result, these compounds could be proposed as a leading compound for further study as a new natural products drug that could be used for diabetic complications. PMID:18670102

Lee, Eun Ha; Song, Dae-Geun; Lee, Joo Young; Pan, Cheol-Ho; Um, Byung Hun; Jung, Sang Hoon

2008-08-01

38

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

39

The development results of the microwave-based device for defect exposure in multi-layer fiberglass plastic structures, polymer and lacquer-and-paint coatings  

Microsoft Academic Search

Presents the development results of a device for defect exposure in flaky multi-layer fiber-glass plastic structures (e.g. airborne radomes) and polymeric and lacquer-and-paint protective coatings. A defects disclosure criterion is based on the analysis of amplitude and phase parameters of incident and reflected waves with the use of special algorithm in non-defect and defective materials. The range of working frequencies

V. R. Dzhala; Ya. M. Kempa; O. B. Lyashchuk; N. A. Naumets; Ya. N. Rybak; G. V. Tsukomyk

2000-01-01

40

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. PMID:24904219

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

2014-01-01

41

Clinical Effects of Rhus coriaria Fruits on Dyslipidemia in Adolescents: a Triple-blinded Randomized Placebo-controlled Trial  

PubMed Central

ABSTRACT Objective: Children and adolescents are considered as the best target groups for preventing and controlling the cardiovascular diseases risk factors and reducing mortality in adulthood. Alternative medicine and herbal drugs have been taken into account for managing dyslipidemia in this population. The beneficial effects of Sumac (Rhus coriaria L.) on lipid profile have been confirmed in some laboratory and animal studies. This study was designed to investigate the clinical effects of sumac fruits on dyslipidemia in 12-18 years-old adolescents. Methods: This randomized triple-blinded clinical trial was conducted on 72 obese adolescents with dyslipidemia from August 2011 to June 2012 in Isfahan Cardiovascular Research Center, Isfahan, Iran. Eligible adolescents were randomly assigned to two case and control groups. The control group received placebo capsules and the case group received capsules containing 500 mg of powdered sumac fruits, each three times a day for one month. Biochemical parameters including 12-hrs fasting serum levels of total cholesterol (Total-C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were measured before the initiation and after the completion of the study protocol. Statistical analysis was performed using the SPSS software, version 16.0, using Independent Samples T-test, or Paired Samples T-test, for between-group and within-group analysis, respectively. Findings: The plasma levels of Total-C, LDL-C, and TG changed significantly over-time in the case group. Furthermore, between-group analysis showed a statistically significant difference between case and control groups with this regard (P < 0.05, for all statistical comparisons). However, HDL-C levels have not been changed significantly over-time within the case or control group, neither between the two study groups. Conclusion: In this study, the considerable effects of Rhus coriaria (sumac) on reducing serum levels of Total-C, LDL-C, and TG have been noticed during one-month trial. However, probably due to the concise period of sumac consumption, its effect on HDL-C was not statistically significant. PMID:25568560

Sabzghabaee, Ali Mohammad; Kelishadi, Roya; Golshiri, Keivan; Ghannadi, Alireza; Badri, Shirinsadat

2014-01-01

42

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

43

Antiplatelet effects of Rhus verniciflua stokes heartwood and its active constituents--fisetin, butein, and sulfuretin--in rats.  

PubMed

Rhus verniciflua stokes (RVS) is known to promote blood circulation by preventing blood stasis, although the active ingredients and the underlying mechanism are unclear. Platelets are the primary cells that regulate circulation and contribute to the development of diverse cardiovascular diseases by aggregation and thrombosis. The study assessed the antiplatelet activity of RVS and sought to identify the active constituents. Pretreatment of washed platelets with RVS heartwood extract blunted the aggregatory response of platelets to collagen. In the subfractions, fisetin, butein, and sulfuretin were identified as effective inhibitors of platelet aggregation by collagen, thrombin, and adenosine-5'-diphosphate. Antiplatelet activities of all three compounds were concentration dependent, and fisetin had longer in vitro duration of action compared with butein or sulfuretin. Extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase activation by collagen was prevented by fisetin, whereas butein and sulfuretin failed to inhibit ERK and p38 activation was not affected by any of the compounds. Rats orally administered 100?mg/(kg·day(-1)) fisetin for 7 days were resistant to arterial thrombosis, although total extract of RVS heartwood exhibited little effect at a dose of 1000?mg/(kg·day(-1)). RVS heartwood may have cardiovascular protective activity by inhibiting platelet aggregation. The active constituents are fisetin, butein, and sulfuretin, and fisetin is orally effective against thrombosis. PMID:25372471

Lee, Jun-Hyeong; Kim, Mikyung; Chang, Kyung-Hwa; Hong, Cheol Yi; Na, Chun-Soo; Dong, Mi-Sook; Lee, Dongho; Lee, Moo-Yeol

2015-01-01

44

Selective cytotoxic effects on human cancer cell lines of phenolic-rich ethyl-acetate fraction from Rhus verniciflua Stokes.  

PubMed

Rhus verniciflua Stokes (RVS) is a plant with a long history of medicinal use in Eastern Asia. RVS has been widely used to treat gastritis, stomach cancer and atherosclerosis. The cytotoxic effects of different solvent fractions from an RVS ethanol extract were measured in 11 human cancer cell lines. The study showed that the ethyl-acetate (EtOAC) fraction was the most cytotoxic. This fraction contains a number of phenolic compounds, and this phenolic-rich EtOAC fraction was particularly effective against gastric and breast cancer cells. A purified phenolic-rich EtOAC fraction (PPEF) had a stronger apoptotic effect on these cells. Liquid chromatography-mass spectrometry (LC-MS) analysis showed that the PPEF contained gallic acid, protocatechuic acid, fisetin, sulfuretin, butein and 8 unknown compounds. There were only small amounts of flavonoids: fisetin, sulfuretin and butein. The results showed that PPEF induces apoptosis only in gastric and breast cancer cell lines, but not in lung, colon or liver cancer cell lines. Therefore, PPEF may have a significant potential as an organ-specific anti-cancer agent. PMID:19606519

Kim, Ji Hye; Jung, Chang Hwa; Jang, Bo-Hyoung; Go, Ho Yeon; Park, Jong-Hyeong; Choi, You-Kyung; Hong, Seong Il; Shin, Yong Cheol; Ko, Seong-Gyu

2009-01-01

45

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

46

Flavonoids purified from Rhus verniciflua Stokes actively inhibit cell growth and induce apoptosis in human osteosarcoma cells.  

PubMed

Many studies have suggested that dietary flavonoids are anticancer agents that induce the apoptosis of cancer cells. However, the effects of flavonoids on the induction of apoptosis in osteosarcoma cells are unclear. Previously, a flavonoid fraction, consisting mainly of protocatechuic acid, fustin, fisetin, sulfuretin, and butein, herein named RCMF (the RVS chloroform-methanol fraction), was prepared from a crude acetone extract of Rhus verniciflua Stokes (RVS). This study evaluated the effects of RCMF on the proliferation and apoptosis using human osteosarcoma (HOS) cells. The mechanism of growth inhibition of the HOS cells by the flavonoid fraction, RCMF, was also assessed. The results demonstrated that RCMF exhibited sensitive growth inhibition and induced apoptosis in HOS cells. PARP cleavage was closely associated with the RCMF-induced apoptosis of the HOS cells. Furthermore, the activation of caspase 8 and Bax, the inhibition of Bcl-2 expression, and the release of cytochrome c are believed to be involved in the RCMF-mediated apoptosis. Collectively, these findings suggest that RCMF is an agent which may be capable of inducing sensitive growth inhibition and apoptosis in HOS cells. PMID:16213662

Jang, Hyon-Seok; Kook, Sung-Ho; Son, Young-Ok; Kim, Jong-Ghee; Jeon, Young-Mi; Jang, Yong-Suk; Choi, Ki-Choon; Kim, Ju; Han, Seong-Kyu; Lee, Kyung-Yeol; Park, Byung-Keon; Cho, Nam-Pyo; Lee, Jeong-Chae

2005-11-30

47

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

48

Preparative isolation and purification of neuroprotective compounds from Rhus verniciflua by high speed counter-current chromatography.  

PubMed

In the present study, extracts from Rhus verniciflua were demonstrated to significantly attenuate the negative effects of hydrogen peroxide (H(2)O(2)) on transformed retinal ganglion cell line (RGC-5 cells), indicating that they may be protective against oxidative stress-induced retinal degeneration. The inclusion of R. verniciflua in the culture was found to both reduce the levels of reactive oxygen species (ROS) present and lessen the up-regulation of apoptotic proteins such as cleaved poly(ADP-ribose) polymerase, cleaved caspase-3, and cleaved caspase-9. Active compounds were also successfully isolated from R. verniciflua using high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (3.5:5:3.5:5, v/v). Using this method, we successfully separated 252.1 mg of fustin at a purity of over 93.09%, 51.2 mg of fisetin at a purity of over 95.45%, 39.7 mg of sulfuretin at a purity of over 95.17%, and 10.7 mg of butein at a purity of over 95.01% from 1.5 g of R. verniciflua extract. The chemical structures of these compounds were elucidated by chemical and spectral analyses. There isolated compounds also significantly attenuated the negative effects of H(2)O(2) on RGC-5 cells. Results therefore suggest that, due to its anti-oxidative and anti-apoptotic effects, R. verniciflua could be used as a lead substance for the treatment of retinal diseases such as glaucoma. PMID:22466561

Choi, Soon Jung; Lee, Min Young; Jo, Hyoung; Lim, Soon Sung; Jung, Sang Hoon

2012-01-01

49

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. PMID:25061471

Jung, Hyunsik; Lee, Sanghun

2014-01-01

50

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

51

Sulfuretin from heartwood of Rhus verniciflua triggers apoptosis through activation of Fas, Caspase-8, and the mitochondrial death pathway in HL-60 human leukemia cells.  

PubMed

Sulfuretin, a flavonoid isolated from heartwood of Rhus verniciflua, has been reported to have anti-cancer activities but the underlying molecular mechanism was not clear. In this study, sulfuretin induced apoptosis by activating caspases-8, -9, and -3 as well as cleavage of poly(ADP-ribose) polymerase. Furthermore, treatment with sulfuretin caused mitochondrial dysfunctions, including the loss of mitochondrial membrane potential (??(m)), the release of cytochrome c to the cytosol, and the translocations of Bax and tBid. Sulfuretin also activated the extrinsic apoptosis pathway, that is, it increased the expressions of Fas and FasL, the activation of caspase-8, and the cleavage of Bid. Furthermore, blocking the FasL-Fas interaction with NOK-1 monoclonal antibody prevented the sulfuretin-induced apoptosis. The therapeutical effect of sulfuretin in leukemia is due to its potent apoptotic activity through the extrinsic pathway driven by a Fas-mediated caspase-8-dependent pathway. PMID:22492309

Lee, Kyung-Won; Chung, Kyung-Sook; Seo, Ji-Hyung; Yim, Sung-Vin; Park, Hee-Jun; Choi, Jung-Hye; Lee, Kyung-Tae

2012-09-01

52

Inhibition of the PI3K-Akt\\/PKB survival pathway enhanced an ethanol extract of Rhus verniciflua Stokes-induced apoptosis via a mitochondrial pathway in AGS gastric cancer cell lines  

Microsoft Academic Search

Rhus verniciflua Stokes (RVS) has been used in traditional Eastern Asia medicine for the treatment of gastritis and stomach cancer, although the mechanism for its biological activity remains to be elucidated. We previously established that an ethanol extract of RVS-induced G1-cell cycle arrest via accumulation of p27Kip1 controlled by Skp2 reduction and apoptosis in AGS human gastric cancer cells. Here,

Ji Hye Kim; Ho Yeon Go; Dong Hoon Jin; Hwang-Phill Kim; Myung Hee Hong; Woo-Yeop Chung; Jong-Hyeong Park; Jun Bock Jang; Hee Jung; Yong Cheol Shin; Sung-Hoon Kim; Seong-Gyu Ko

2008-01-01

53

What is a Tree? Tree terminology  

E-print Network

1 Trees · What is a Tree? · Tree terminology · Why trees? · What is a general tree? · Implementing trees · Binary trees · Binary tree implementation · Application of Binary trees #12;2 What is a Tree? · A tree, is a finite set of nodes together with a finite set of directed edges that define parent

Razak, Saquib

54

Tree Tally  

NSDL National Science Digital Library

In this outdoor activity and fun race, learners first find the most common type of tree in a forest site. Learners use a "transect," a kind of sampling technique, to estimate the number of different kinds of trees, and a histogram, or simple graph, to record how frequently different tree species occur in the forest. Learners also select one species of tree, and run a forest leap frog race between trees of that species. (Older learners can just run between trees without leapfrogging.)

Lawrence Hall of Science

1982-01-01

55

Test method for measuring non-visible set-off from inks and lacquers on the food-contact surface of printed packaging materials.  

PubMed

The main objective was to develop a technique to expose spots of invisible set-off of inks and lacquers on the food-contact surface of food-packaging materials. Set-off is the unintentional transfer of components of printing inks from the outer printed surface onto the food-contact surfaces. The target sensitivity was 20 microg cm(-2) and the technique should be capable of examining large areas of printed substrate for no more than 4% coverage by set-off. These requirements equate to an ability to detect a worst-case migration potential of less than 50 microg kg(-1). Other objectives were the industrial requirements that the equipment should be inexpensive, should be easy to use by existing personnel and should preferably be non-destructive with a clear criterion for pass or fail. The approaches investigated included chemical analysis of solvent extracts, Fourier-transform infrared spectroscopy and microbeam analytical techniques, but these were found to be cumbersome and had only limited success. The objectives were achieved using an optical approach to excite and observe luminescence from invisible set-off. In model experiments, resins were applied to different substrates (plastic, paper and cartonboard). For a given resin on a given material, the key to success was to maximize the discrimination between the luminescence from the resin and that from the substrate by selecting the optimal combination of exciting wavelength and viewing goggles with selective wavelength filters. The required level of detection (20 microg cm(-2)) was achieved or exceeded for all ten resins tested on three different plastics. It was also achieved for two different papers and in all but four cases of the resins on three different cartonboards. Quantitation was achieved by the use of a calibration palette prepared using different quantities of resin spotted onto the relevant blank packaging material. PMID:16019822

Bradley, E L; Castle, L; Dines, T J; Fitzgerald, A G; Gonzalez Tunon, P; Jickells, S M; Johns, S M; Layfield, E S; Mountfort, K A; Onoh, H; Ramsay, I A

2005-05-01

56

Flower Face Face Face Face Flower Tree Tree Tree Tree  

E-print Network

Flower Flower Flower Flower Flower Face Face Face Face Flower Flower Tree Tree Tree Tree Flower Flower Flower Flower Sky Sky Sky Sky Flower Grass Grass Grass Grass Flower Flower Flower #12;Sign Sign Road Road Chair Face Face Face Face Chair #12;Chair Chair Chair Flower Flower Flower Flower Grass Chair

Chen, Tsuhan

57

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

58

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

59

Rhus verniciflua stokes extract: radical scavenging activities and protective effects on H2O2-induced cytotoxicity in macrophage RAW 264.7 cell lines.  

PubMed

The goal of this study was to determine the effects of Rhus verniciflua stokes (RVS) on the radical scavenging activities and H2O2-induced cytotoxicity in macrophage 264.7 cells. An 80% ethanol extract of RVS was purified by ion exchange chromatography (IEC). Purified RVS extract contained a high amount of phenolics (55.5 g/100 g of extract) and flavonoids (5.9 g/100 g of extract) and its antioxidant activities, such as DPPH, superoxide anion and hydroxyl radical scavenging activities, was higher than the unpurified RVS extract. Purified RVS extract significantly reduced intracellular ROS formation caused by H2O2. Purified RVS extract also prevented the cell death of macrophage RAW 264.7 cells induced by H2O2. Interestingly, co-treated purified RVS extract effectively reduced thiobarbituric acid reactive substance (TBARS) formation, and attenuated catalase depletion at concentration of 100 microg/ml (p<0.05). Study using PDA-HPLC analyses have found that the purified RVS extract contains six major low molecular compounds as p-coumaric acid, fustin, kaempferol-3-O-glucoside, sulfuretin, butein and kaempferol. These results indicate that purified RVS extract, tested in this study, could contribute to the antioxidant activities and inhibition of intracellular ROS level. PMID:16880612

Jung, Chang Hwa; Jun, Chan-Yong; Lee, Sundong; Park, Chong-Hyeong; Cho, Kiho; Ko, Seong-Gyu

2006-08-01

60

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. PMID:23710214

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

2013-01-01

61

Microelement contents and fatty acid compositions of Rhus coriaria L. and Pistacia terebinthus L. fruits spread commonly in the south eastern Anatolia region of Turkey.  

PubMed

Sumac (Rhus coriaria L.) and terebinth (Pistacia terebinthus L.) are two important spice plants of south eastern Anatolia, Turkey. Nutrients, physical properties including moisture, ash, dry matter, protein, fatty oil and essential oil content, along with Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Na, Ni, Pb, Zn and characteristics of fruit sizes and fatty acid compositions of both plants were determined from ripe fruits. The free fatty acid content was determined in the fruit oil, and the main fatty acids of sumac and terebinth were identified by gas chromatography/mass spectrometry. They included oleic, linoleic, palmitic and stearic acids in a ratio of 37.7% and 34.8%, 27.4% and 17.3%, 21.1% and 21.7% and, 4.7% and 2.5%, respectively. The fruits of both plants were rich in oil, fatty acids and minerals, suggesting that they are valuable for using in food. The data may also be useful for the evaluation of nutritional information. PMID:20013479

Kizil, Suleyman; Turk, Murat

2010-01-01

62

Decision Trees Unpredictability Bias Improvements Decision Trees  

E-print Network

Decision Trees Unpredictability Bias Improvements Decision Trees #12;Decision Trees Unpredictability Bias Improvements 1 Decision Trees Using Trees Learning 2 Unpredictability Entropy Entropy for datasets Information Gain 3 Bias Bias Occam's principle Overfitting 4 Improvements #12;Decision Trees

Kjellström, Hedvig

63

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

64

The effect of sumac (Rhus coriaria L.) powder on insulin resistance, malondialdehyde, high sensitive C-reactive protein and paraoxonase 1 activity in type 2 diabetic patients  

PubMed Central

Background: Sumac (Rhus coriaria L.) has been used in traditional treatment of some diseases. The aim of this study was to determine the effect of sumac (R. coriaria L.) powder on insulin resistance (IR), malondialdehyde (MDA), high sensitive C-reactive protein (hs-CRP), and paraoxonase 1 (PON1) activity in type 2 diabetic patients. Materials and Methods: A double-blind randomized placebo controlled trial on 41 type 2 diabetic volunteers was conducted. Participants randomly assigned into 3 g per day sumac powder (n = 22) or placebo (n = 19) groups for 3 months. IR was assessed using the homeostatic model assessment of IR (HOMA-IR), which including measurement of insulin by immunoassay method and measurement of glucose by enzymatic method. MDA and PON1 activity were measured colorimetrically, hs-CRP turbidimetrically. Results: There were a significant increase in PON1 activity (from 84.72 ± 30.59 to 92.91 ± 32.63) and significant decrease in insulin (from 7.09 ± 4.28 to 5.32 ± 3.22), HOMA-IR (from 2.56 ± 1.58 to 1.67 ± 0.94), MDA (from 2.71 ± 0.73 to 1.97 ± 0.49), and also hs-CRP (from 18.49 ± 16.96 to 15.89 ± 16.70) in the sumac group at the end of study compared with initial values (P < 0.05). Furthermore, there were significant differences in MDA and PON1 between the two groups at the end of the study (P < 0.05). Furthermore, the mean of differences of insulin, HOMA-IR, MDA, hs-CRP and PON1 activity between groups were significant (P < 0.05). Conclusion: We concluded that daily intake of 3 g sumac for 3 months may be beneficial for diabetic patients to make them less susceptible to cardiovascular disease. PMID:25538775

Rahideh, Seyedeh Tayebeh; Shidfar, Farzad; Khandozi, Nafiseh; Rajab, Asadollah; Hosseini, Seyed Payam; Mirtaher, Seyed Mohsen

2014-01-01

65

Effects of Hydro-Alcoholic Extract of Rhus coriaria (Sumac) Seeds on Reproductive Complications of Nicotinamide-Streptozotocin Induced Type-2 Diabetes in Male Mice  

PubMed Central

Purpose The purpose of this study was to investigate the effects of the hydro-alcoholic extract of Rhus coriaria seeds on the reproductive system of nicotinamide-streptozotocin-induced type-2 diabetic mice. Materials and Methods In this experimental study, 56 male Naval Medical Research Institute mice were randomly divided into seven groups (n=8): control; diabetic mice; diabetic mice administered glibenclamide (0.25 mg/kg); diabetic mice who received the hydro-alcoholic extract of R. coriaria seeds (200 and 400 mg/kg groups); and normal mice who received this extract (200 and 400 mg/kg groups). Diabetes was induced by intraperitoneal administration of streptozotocin (65 mg/kg) 15 minutes after an injection of nicotinamide (120 mg/kg). Then, glibenclamide and the above mentioned extract were administered orally for 28 consecutive days. Twenty-four hours after the last treatment, serum samples, the testes, and the cauda epididymis were removed immediately for hormonal, testis morphology, and sperm parameter assessments. Results Body and testicular weight, sperm count and viability, and serum luteinizing hormone, follicle-stimulating hormone and testosterone levels were significantly lower in the diabetic mice (p<0.05). The diabetic mice treated with 400 mg/kg of the hydro-alcoholic extract of R. coriaria seeds recovered from these reductions (p<0.05). Further, glibenclamide alleviated hormonal and sperm count depletion in diabetes-induced mice (p<0.05). Conclusions The present results indicated that the hydro-alcoholic extract of R. coriaria seeds has anti-infertility effects in diabetic males. PMID:25606564

Ahangarpour, Akram; Heidari, Hamid; Ehsan, Ghaedi; Rashidi Nooshabadi, Mohammad Reza

2014-01-01

66

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

67

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

68

INCREASING TREE FAMILIES Michael Drmota  

E-print Network

INCREASING TREE FAMILIES Michael Drmota Inst. of Discrete Mathematics and Geometry Vienna · Recursive Trees · Plane Oriented Trees · General Increasing Trees · Degree Distribution · Conclusion #12;Recursive Trees #12;Recursive Trees #12;Recursive Trees #12;Recursive Trees #12;Recursive Trees #12

Drmota, Michael

69

Talking Trees  

ERIC Educational Resources Information Center

Students love outdoor activities and will love them even more when they build confidence in their tree identification and measurement skills. Through these activities, students will 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…

Tolman, Marvin

2005-01-01

70

Tree Talk  

NSDL National Science Digital Library

In this math meets life science lesson, learners measure the circumference of local trees in order to calculate diameters. Learners use this information and a growth rate table to estimate the age of the trees. This lesson guide includes questions for learners, assessment options, extensions, and reflection questions.

S. Rosen

2010-01-01

71

Growing Tree  

NSDL National Science Digital Library

Includes RedBlackTrees, BinarySearchTrees, and SplayTrees. It allows the user to create randomly generated input data or to insert user's own input data for a splay tree in different formats such as integer, double, and character. Users can construct a splay tree by directly inserting, deleting, and splaying tree nodes to the top. The user can also select different tree operations such as in, pre- and post-order traversals. It provides a number of flexible user controls including the speed control, stop, forward, backward steps, etc. Text-based descriptions are displayed for each algorithm step. The textual descriptions include miscellaneous information about the tree including the size, number of elements and depth. This text information can define a history of the algorithm. One of the best AVs for the splay tree. It provides interaction-oriented operations and adjustable spatial layout with intuitive animations. This AV includes almost all necessary features for the splay tree. Randomly generated input data offered many advantages for a beginner to start with some input. It also allows constructing the splay tree with user's own input dataset. The graphic representation and animation for the splay tree is intuitive and helpful for understanding each algorithm step. A small text window lists algorithm steps that are performed. The AV has a simple, intuitive interface. For new users, it can be difficult to get started, though, since there is no help facility or introduction to the AV. The user can select a node by clicking it. A context menu then appears which allows double rotation, splay to the top, and delete. Controls at the top allow nodes to be inserted. There are some weaknesses.The layout is spacious but the number representation seems sometimes misleading during the animation and transformation. There is a problem with scalability of nodes in representation of the tree. When the number of elements in the tree grows beyond 10, the nodes become too small for the user to read. There is no quiz or exercise mode to encourage self-evaluation. Some controls ambiguous . For example, although those controls present on the interface menu, backwards and forwards steps of the animation don't seem to do anything. The history window is too small. Recommended as lecture aide, standalone, self-study suppliment to tutorial or lecture.

Bob Sedgewick

72

Inferring trees.  

PubMed

Molecular phylogenetics examines how biological sequences evolve and the historical relationships between them. An important aspect of many such studies is the estimation of a phylogenetic tree, which explicitly describes evolutionary relationships between the sequences. This chapter provides an introduction to evolutionary trees and some commonly used inferential methodology, focusing on the assumptions made and how they affect an analysis. Detailed discussion is also provided about some common algorithms used for phylogenetic tree estimation. Finally, there are a few practical guidelines, including how to combine multiple software packages to improve inference, and a comparison between Bayesian and maximum likelihood phylogenetics. PMID:18566770

Whelan, Simon

2008-01-01

73

Factor Trees  

NSDL National Science Digital Library

In this online activity, the learner finds the prime factorization of composite numbers by building factor trees. A second level includes finding the greatest common factor and the least common multiple by sorting factors using a Venn Diagram.

2010-01-01

74

Factor Trees  

NSDL National Science Digital Library

This virtual manipulative allows students to find the prime factorization of numbers by completing factor trees. Then they may use a venn diagram to sort the prime factors to find the greatest common factor and the least common multiple.

Math Playground

2009-07-29

75

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

76

Community Trees Community Tree Steward Program  

E-print Network

1 Community Trees Community Tree Steward Program ...and justice for all The U.S. Department, Iowa February, 2001 Jeff Iles Department of Horticulture Iowa State University Most tree managers realize dead trees should be removed as soon as they are detected. But living trees also can be a threat

Koford, Rolf R.

77

Community Trees Power Lines and Trees  

E-print Network

Community Trees Power Lines and Trees Introduction Trees serve many purposes in urban and rural trees near power lines. Most high voltage lines are not insulated, and contact will result in electric areas. To assure safe and reliable electric service, trimming or removal of trees is sometimes necessary

Koford, Rolf R.

78

Minimizing Tree Automata for Unranked Trees  

E-print Network

Minimizing Tree Automata for Unranked Trees Wim Martens Joachim Niehren Minimizing Tree Automata for Unranked Trees ­ p.1/20 #12;What and Why? To study the minimization problem for deterministic automata over unranked trees. Bottom-up deterministic: theoretical interest. E.g. do results from deterministic automata

Martens, Wim

79

Community Trees Community Tree Steward Program  

E-print Network

-sized shade tree, yet in many urban sites, trees are routinely confined to tree pits that provide a paltry 401 Community Trees Community Tree Steward Program ...and justice for all The U.S. Department environmental requirements for plant growth include adequate space for root and canopy development, sufficient

Koford, Rolf R.

80

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.

Keith Addison

2010-01-01

81

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

82

Shade trees  

Microsoft Academic Search

Shading is an important part of computer imagery, but shaders have been based on fixed models to which all surfaces must conform. As computer imagery becomes more sophisticated, surfaces have more complex shading characteristics and thus require a less rigid shading model. This paper presents a flexible tree-structured shading model that can represent a wide range of shading characteristics. The

Robert L. Cook

1984-01-01

83

Tea tree oil  

MedlinePLUS

Tea tree oil is derived from the leaves of the tea tree. The tea tree was named by eighteenth century sailors, who made ... smelled like nutmeg from the leaves of the tree growing on the swampy southeast Australian coast. Do ...

84

Urban tree mortality  

E-print Network

for managing the urban canopy, in terms of tree removal andurban tree planting initiatives, these trees must survive to maturity, when canopyurban forest programs. Fifteen percent would like researchers to provide accurate estimates of tree mortality, growth, and canopy

Roman, Lara Angelica

2013-01-01

85

TREES, WOODS AND FORESTS  

E-print Network

SCOTLAND'S TREES, WOODS AND FORESTS #12;2 SCOTLAND'S TREES, WOODS AND FORESTS2 #12;SCOTLAND'S TREES FOR THE ENVIRONMENT CHAPTER 4 FORESTS FOR THE ECONOMY CHAPTER 5 SCOTLAND'S REMARKABLE TREES CHAPTER 6 FINDING OUT MORE SCOTLAND'S TREES, WOODS AND FORESTS #12;4 SCOTLAND'S TREES, WOODS AND FORESTS4 This booklet is written

86

Technical Tree Climbing.  

ERIC Educational Resources Information Center

Tree climbing offers a safe, inexpensive adventure sport that can be performed almost anywhere. Using standard procedures practiced in tree surgery or rock climbing, almost any tree can be climbed. Tree climbing provides challenge and adventure as well as a vigorous upper-body workout. Tree Climbers International classifies trees using a system…

Jenkins, Peter

87

Tree Link  

NSDL National Science Digital Library

This site was created to provide information, research, and networking for people working in urban and community forestry. It is meant to inform, educate, and inspire the researcher, arborist, community group leader, and volunteer. The site contains: educational materials, how-to guides, a research database, discussion forums, a quarterly web-zine, a comprehensive link list of national and local resources, late-breaking news, interactive tools for tree identification and selection, and an Ask an Arborist section.

88

Tree Torture  

NSDL National Science Digital Library

The San Pedro River is one of the only free-flowing waterways in Arizona. Though it's more of a small stream than a river, it nourishes a vibrant ecosystem known as a riparian area. Full of tall trees, it serves as a major flyway for migrating birds and provides a ribbon of green in an otherwise barren landscape. In this Science Update, you'll hear about the research being done to keep the San Pedro flowing.

Science Update

2002-06-10

89

What Makes a Tree a Tree?  

ERIC Educational Resources Information Center

Provides: (1) background information on trees, focusing on the parts of trees and how they differ from other plants; (2) eight activities; and (3) ready-to-copy pages dealing with tree identification and tree rings. Activities include objective(s), recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

NatureScope, 1986

1986-01-01

90

Parallelization: Binary Tree Traversal  

NSDL National Science Digital Library

This module teaches the use of binary trees to sort through large data sets, different traversal methods for binary trees, including parallel methods, and how to scale a binary tree traversal on multiple compute cores. Upon completion of this module, students should be able to recognize the structure of a binary tree, employ different methods for traversing a binary tree, understand how to parallelize a binary tree traversal, and how to scale a binary tree traversal over multiple compute cores.

Aaron Weeden

91

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.

92

Phenolic-rich fraction from Rhus verniciflua Stokes (RVS) suppress inflammatory response via NF-kappaB and JNK pathway in lipopolysaccharide-induced RAW 264.7 macrophages.  

PubMed

The effects of phenolic-rich fraction (PRF) from Rhus verniciflua Stokes (Anacardiaceae) on the activities of cellular signaling molecules that mediate inflammatory responses in LPS-induced RAW 264.7 macrophages were investigated. At various concentrations of PRF significantly inhibited NO, PGE(2) and TNF-alpha production in LPS-induced RAW 264.7 macrophage cells. The PRF also significantly inhibited iNOS and COX-2 protein expression in LPS-induced RAW 264.7 macrophage in a concentration-dependent manner. Transcription factor NF-kappaB plays a key role for the inducible expression of genes mediating proinflammatory effects and here, we show that PRF can inhibit the induction of NF-kappaB activity. The PRF effectively inhibited the iNOS and COX-2 protein expression through suppression of phospho-JNK1/2 activation. Study using PDA HPLC has found that the PRF contains several low molecular compounds (i.e. p-coumaric acid, fustin, kaempferol-3-O-glucoside, sulfuretin, butein, kaempferol). Our results indicate that the anti-inflammatory properties of PRF might result from the inhibition of pro-inflammatory mediators (e.g., NO, PGE(2) and TNF-alpha) by suppression of such signaling pathways as NF-kappaB and JNK1/2. PMID:17112694

Jung, Chang Hwa; Kim, Ji Hye; Hong, Myung Hee; Seog, Ho Moon; Oh, Seong Hoon; Lee, Pan Jae; Kim, Gyung Jun; Kim, Hyung Min; Um, Jae Young; Ko, Seong-Gyu

2007-04-01

93

Ancient trees in Amazonia  

Microsoft Academic Search

The ages of tropical rain forest trees provide critical information for understanding the dynamics of tree populations, determining historical patterns of disturbance, developing sustainable forestry practices and calculating carbon cycling rates. Nevertheless, the ecological life history of most tropical trees is unknown and even the ages of the largest trees remain to be determined. Tree ages are typically measured by

Jeffrey Q. Chambers; Niro Higuchi; Joshua P. Schimel

1998-01-01

94

The Tree Worker's Manual.  

ERIC Educational Resources Information Center

This manual is designed to prepare students for entry-level positions as tree care professionals. Addressed in the individual chapters of the guide are the following topics: the tree service industry; clothing, eqiupment, and tools; tree workers; basic tree anatomy; techniques of pruning; procedures for climbing and working in the tree; aerial…

Smithyman, S. J.

95

Tea Tree Oil  

MedlinePLUS

... Services National Institutes of Health Search NIH…Turning Discovery Into Health ® Follow NCCAM: Read our disclaimer about external links Read our disclaimer about external links Menu Tea Tree Oil Common Names: Australian tea tree oil, tea tree ...

96

Minnesota Tree Blitz  

NSDL National Science Digital Library

In this biology field experience, students will explore trees of Minnesota. Working in cooperative groups, students will discover biodiversity of trees and determine populations of tree species through observation and use of dichotomous keys.

97

American Chestnut Tree  

NSDL National Science Digital Library

This annotated slideshow adapted from KET's Electronic Field Trip to the Forest illustrates how blight decimated the American chestnut tree and the methods scientists use to identify and pollinate the remaining trees to create blight-resistant trees.

2008-08-25

98

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.

99

Tree Growth Investigation  

NSDL National Science Digital Library

This activity (located on page 3 of the PDF) is a full inquiry investigation into tree growth rates. Groups of learners will count tree rings to determine each tree’s age. A thorough sample of other measurements will then be taken to calculate the trees’ fastest, slowest, and overall average growth rate. Presenting the results in a table allows learners to compare data for different types of trees. Relates to linked video, DragonflyTV GPS: Temperate Rainforest.

Twin Cities Public Television, Inc.

2007-01-01

100

Structure i-Tree Tree Eco Overview  

E-print Network

The Davey InstituteHow do we communicate the value of the resource at risk? Evanston has over 4,000 ash trees on its parkways and in its parks, which is about 12 % of the City of Evanston’s 33,000 public trees. Evanston resource at risk to EAB 3500 ash street trees 10.5 % of public trees $3.18 million structural value 4.9 million gal/yr of rainfall intercepted worth $135,000/yr $122,000/yr energy savings $20,350/yr in air quality improvement $113,000 annual CO2 valueCan you justify your needsIncreasing Public Scrutinyi-Tree Tree Backgroundi-Tree Tree Includes…

Urban Forest; Al Zelaya; Urban Forest; Canopy Loss; Ufore Assessing Urban Ecosystems

101

Protected trees A guide to tree preservation procedures  

E-print Network

Protected trees A guide to tree preservation procedures #12;Protected trees A guide to tree trees: A guide to tree preservation procedures Introduction This leaflet is written for tree owners, their neighbours and local community groups, and answers some of the most common questions about tree preservation

102

Essential Kurepa Trees Versus Essential Jech Kunen Trees1  

E-print Network

Essential Kurepa Trees Versus Essential Jech Kunen Trees1 Renling Jin2 & Saharon Shelah3 Abstract By an !1 tree we mean a tree of cardinality !1 and height !1. An !1 tree is called a Kurepa tree if all its levels are countable and it has more than !1 branches. An !1 tree is called a Jech Kunen tree if it has

Jin, Renling

103

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. PMID:22645486

Qasem, Jamal R.

2012-01-01

104

Ephedra alte (joint pine): an invasive, problematic weedy species in forestry and fruit tree orchards in Jordan.  

PubMed

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. PMID:22645486

Qasem, Jamal R

2012-01-01

105

A tree-to-tree model for statistical machine translation  

E-print Network

In this thesis, we take a statistical tree-to-tree approach to solving the problem of machine translation (MT). In a statistical tree-to-tree approach, first the source-language input is parsed into a syntactic tree ...

Cowan, Brooke A. (Brooke Alissa), 1972-

2008-01-01

106

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

107

Minimum Spanning Tree Jayadev Misra  

E-print Network

Minimum Spanning Tree Jayadev Misra 12/12/98 1 Spanning Tree A spanning tree of an undirected graph for finding the minimum spanning tree. Properties of spanning trees In a spanning tree: · There is no cycle edges have non-negative weights. A minimum span- ning tree is a spanning tree whose total edge weight

Misra, Jayadev

108

Oxidant air pollution effects on plants of Joshua Tree National Monument.  

PubMed

Joshua Tree National Monument (JOTR) is located about 100 km east of the Los Angeles Basin, site of the heaviest concentration of photochemical oxidant (O(3)) air pollution in the US. This investigation was conducted to measure O(3) concentrations in JOTR and to determine the effects of O(3) on vegetation in the park. Potentially phytotoxic concentrations of O(3) were recorded in JOTR in 1984 and 1985, but peak concentration occurred at night, when most plant species would be less sensitive to O(3). No O(3) effects were observed on permanent vegetation observation plots in JOTR in 1984 or 1985. Controlled exposures of native summer annual and woody perennial species to O(3) showed that most did not develop visible O(3) injury symptoms except at concentrations higher than those expected in the park. However, Rhus trilobata Nutt. was injured at 0.10 ppm O(3), 4 h per day for 4 days. This species would be a useful bioindicator to assess the effects of O(3) on native desert plants. PMID:15092465

Temple, P J

1989-01-01

109

Limit Laws for Functions of Fringe trees for Binary Search Trees and Recursive Trees  

E-print Network

Limit Laws for Functions of Fringe trees for Binary Search Trees and Recursive Trees Cecilia of binary search trees and random recursive trees. In particular, we give simple new proofs of the fact that the number of fringe trees of size k = kn in the binary search tree and the random recursive tree (of total

Janson, Svante

110

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

111

Random Trees and Applications  

E-print Network

Random Trees and Applications Jean-Fran¸cois Le Gall1 Notes prepared for the Cornell Summer School;2 #12;Chapter 1 From Discrete to Continuous Trees In this chapter, we first explain how discrete random trees can be coded by discrete paths called the height function and the contour function of the tree. We

Durrett, Richard

112

The Needs of Trees  

ERIC Educational Resources Information Center

Tree rings can be used not only to look at plant growth, but also to make connections between plant growth and resource availability. In this lesson, students in 2nd-4th grades use role-play to become familiar with basic requirements of trees and how availability of those resources is related to tree ring sizes and tree growth. These concepts can…

Boyd, Amy E.; Cooper, Jim

2004-01-01

113

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. PMID:23950877

Fisler, Marie; Lecointre, Guillaume

2013-01-01

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

The Effect of Sumac (Rhus coriaria L.)Powder on Serum Glycemic Status, ApoB, ApoA-I and Total Antioxidant Capacity in Type 2 Diabetic Patients  

PubMed Central

Sumac (Rhus coriaria L.) is used as an herbal remedy in traditional medicine. The aim of this study was to determine the effects of sumac (R. coriaria) on serum glycemic status, apolipoprotein (apo) B, apoA-I and total antioxidant capacity (TAC) in type 2 diabetic patients. This double blind randomized controlled clinical trial was conducted on 41type 2 diabetic volunteers randomly assigned into 3g/day sumac powder (n=22) or placebo (n=19) groups over 3 months. Blood samples were collected before and after the intervention. Serum glucose and HbA1c were measured using enzymatic and turbidimetric inhibition immunoassay methods, respectively. ApoB, apoA-I and TAC were determined using turbidimetric immunoassay and spectrophotometric methods, respectively. There were signi?cant decreases in serum glucose and HbA1c and also apoB levels at the end of study compared with initial values (P< 0.0001, P= 0.002 and P< 0.0001,respectively). Also, there was a significant difference in HbA1c and TAC levels between placebo and sumac groups at the end of study (P< 0.05).In sumac group, there were significant increase in apoA-I and TAC(P< 0.0001) compared with initial values. The mean of differences of serum glucose, HbA1c, apoB, apoA-I, apoB/apoA-I ratio and TAC between groups were significant (P< 0.05). In conclusion, these results showed the favorite effect of sumac consumption on serum glycemic status, apoB, apoA-I and TAC levels in in type 2 diabetic patients. PMID:25587314

Shidfar, Farzad; Rahideh, Seyedeh Tayebeh; Rajab, Asadollah; Khandozi, Nafise; Hosseini, Sharieh; Shidfar, Shahrzad; Mojab, Faraz

2014-01-01

116

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

117

Water treeing in polyethylene cables  

Microsoft Academic Search

Water tree growth in polyethylene cable insulation is discussed. The characteristics of water trees, the effect of aging parameters on water tree growth, and the possible mechanisms of growth are considered, emphasizing vented tree development in polyethylene insulating materials. The morphology of water trees, the characteristics of the tree-infested dielectric cable, and test methods and measures to reduce water treeing

E. F. Steennis; F. H. Kreuger

1990-01-01

118

COMPONENT User's Guide Random trees  

E-print Network

COMPONENT User's Guide Chapter 6 Random trees COMPONENT can generate a variety of trees at "random," and for small numbers of leaves it can generate all possible trees. These trees have several uses: n as user trees for phylogeny programs that lack the facility to examine all trees or sets of random trees (e

Page, Roderic

119

From Gene Trees to Species Trees II: Species Tree Inference by Minimizing Deep  

E-print Network

From Gene Trees to Species Trees II: Species Tree Inference by Minimizing Deep Coalescence Events Louxin Zhang Abstract--When gene copies are sampled from various species, the resulting gene tree might disagree with the containing species tree. The primary causes of gene tree and species tree discord include

Zhang, Louxin

120

Paint, lacquer, and varnish remover poisoning  

MedlinePLUS

... control or a health care professional. If the chemical was swallowed, immediately give the person water or milk, unless instructed otherwise by a health care provider. If the person breathed in the poison, immediately move him or her to fresh air.

121

Tree Decline Shade trees often gradually lose  

E-print Network

observed in the aboveground parts of the plant usually begin in the root system. Stress Factors Trees conditions, and other environmental effects. These are often called "stress factors" and alone or collectively reduce growth and may cause dieback of the tree. The root system is espe- cially vulnerable

122

Tree Classification Software  

NASA Technical Reports Server (NTRS)

This paper introduces the IND Tree Package to prospective users. IND does supervised learning using classification trees. This learning task is a basic tool used in the development of diagnosis, monitoring and expert systems. The IND Tree Package was developed as part of a NASA project to semi-automate the development of data analysis and modelling algorithms using artificial intelligence techniques. The IND Tree Package integrates features from CART and C4 with newer Bayesian and minimum encoding methods for growing classification trees and graphs. The IND Tree Package also provides an experimental control suite on top. The newer features give improved probability estimates often required in diagnostic and screening tasks. The package comes with a manual, Unix 'man' entries, and a guide to tree methods and research. The IND Tree Package is implemented in C under Unix and was beta-tested at university and commercial research laboratories in the United States.

Buntine, Wray

1993-01-01

123

Minimal locked trees  

E-print Network

Locked tree linkages have been known to exist in the plane since 1998, but it is still open whether they have a polynomial-time characterization. This paper examines the properties needed for planar trees to lock, with a ...

Ballinger, Brad

124

Graph homomorphisms between trees  

E-print Network

In this paper we study several problems concerning the number of homomorphisms of trees. We begin with an algorithm for the number of homomorphisms from a tree to any graph. By using this algorithm and some transformations ...

Csikvari, Peter

125

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

126

Grizzly Giant Tree  

USGS Multimedia Gallery

This giant sequoia is named the Grizzly Giant, the oldest sequoia tree in the Mariposa Grove of Big Trees, located within Yosemite National Park. It is believed to be between 1,900 and 2,400 years old. ...

127

Tree SelectionTree Selection Why is selection important?  

E-print Network

Tree SelectionTree Selection #12; Why is selection important? What happens when we think it's not important? Not all trees grow alike Incompatible situation Average life span of city tree is 7-13 years end up with a tree in the wrong location. #12;Tree Selection Style I Let's Try Another Selection

128

Minimum Spanning Tree What is a Minimum Spanning Tree.  

E-print Network

Minimum Spanning Tree · What is a Minimum Spanning Tree. · Constructing Minimum Spanning Trees. · What is a Minimum-Cost Spanning Tree. · Applications of Minimum Cost Spanning Trees. · Prim's Algorithm;What is a Minimum Spanning Tree. · Let G = (V, E) be a simple, connected, undirected graph

Razak, Saquib

129

Balancing Minimum Spanning Trees and Shortest-Path Trees  

Microsoft Academic Search

We give a simple algorithm to find a spanning tree that simultaneously approximates a shortest-path tree and a minimum spanning tree. The algorithm provides a continuous tradeoff: given the two trees and a 7 > 0, the algorithm returns a spanning tree in which the distance between any vertex and the root of the shortest-path tree is at most 1

Samir Khuller; Balaji Raghavachari; Neal E. Young

1995-01-01

130

Binary Search Trees Page 1 Binary Search Trees  

E-print Network

Binary Search Trees Page 1 Chapter 4 Trees Binary Search Trees · Definition o All keys are distinct subtree is greater than the root. o Left and right subtrees are binary search trees. · Figure 1 is an example: Figure 1 Binary Search Tree · Where would you add X, B, and E? · At seats, build tree from

Allan, Vicki H.

131

8-ary tree. Overview of B-Trees  

E-print Network

Page Page Figure A.1 8-ary tree. APPENDIX A Overview of B-Trees Tree-based searching methods large, we find that often the tree is too large to fit in memory at once. Therefore, the tree is stored. In such an environment, the branches in the tree contain disk addresses, and it is not uncommon for a comparison

Yorke, James

132

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.

University of Nebraska State Museum

2001-01-01

133

Kids for Trees  

NSDL National Science Digital Library

This website provides references for students about the importance of trees to people and the environment. It discusses the interactions between trees and other organisms, how trees provide for their food and water needs, and how people use and work with trees. A teacher's guide provides background information, project and activity ideas, evaluation questions, and extensions that correspond with each student reference page. Links to related resources are included.

134

Symbolic Tree Transducers  

Microsoft Academic Search

Symbolic transducers are useful in the context of web security as they form the foundation for sanitization of potentially malicious data. We define Symbolic Tree Transducers as a generalization of Regular Transducers as finite state input-output tree automata with logical constraints over a parametric background theory. We examine key closure properties of Symbolic Tree Transducers and we develop a composition

Margus Veanes; Nikolaj Bjorner

2011-01-01

135

Overprvning Large Decision Trees  

Microsoft Academic Search

This paper presents empirical evidence for five hypotheses about learning from large noisy domains: that trees built from very large training sets are larger and more accurate than trees built from even large subsets; that this increased accuracy is only in part due to the extra size of the trees; and that the extra training instances allow both better choices

Jason Catlett

1991-01-01

136

Marrying Words and Trees  

Microsoft Academic Search

Traditionally, data that has both linear and hierarchical structure, such as annotated linguistic data, is modeled us- ing ordered trees and queried using tree automata. In this paper, we argue that nested words and automata over nested words oer a better way to capture and process the dual structure. Nested words generalize both words and ordered trees, and allow both

Rajeev Alur

2007-01-01

137

Multiclass Alternating Decision Trees  

Microsoft Academic Search

The alternating decision tree (ADTree) is a successful clas- sication technique that combines decision trees with the predictive ac- curacy of boosting into a set of interpretable classication rules. The original formulation of the tree induction algorithm restricted atten- tion to binary classication problems. This paper empirically evaluates several wrapper methods for extending the algorithm to the multiclass case by

Geoffrey Holmes; Bernhard Pfahringer; Richard Kirkby; Eibe Frank; Mark Hall

2002-01-01

138

Representing Trees with Constraints   

E-print Network

This paper presents a method for representing trees using constraint logic programming over finite domains. We describe a class of trees that is of particular interest to us and how we can represent the set of trees belonging to that class using...

Curry, Benjamin; Wiggins, Geraint; Hayes, Gillian

139

Winter Birch Trees  

ERIC Educational Resources Information Center

Trees are great inspiration for artists. Many art teachers find themselves inspired and maybe somewhat obsessed with the natural beauty and elegance of the lofty tree, and how it changes through the seasons. One such tree that grows in several regions and always looks magnificent, regardless of the time of year, is the birch. In this article, the…

Sweeney, Debra; Rounds, Judy

2011-01-01

140

Boosting Decision Trees  

Microsoft Academic Search

A new boosting algorithm of Freund and Schapire is used to improve the performance of decision trees which are constructed usin: the information ratio criterion of Quinlan's C4.5 algorithm. This boosting algorithm iteratively constructs a series of decision tress, each decision tree being trained and pruned on examples that have been filtered by previously trained trees. Examples that have been

Harris Drucker; Corinna Cortes

1995-01-01

141

Fault Tree Analysis  

Microsoft Academic Search

In this chapter, a state-of-the-art review of fault tree analysis is presented. Different forms of fault trees, including\\u000a static, dynamic, and non-coherent fault trees, their applications and analyses will be discussed. Some advanced topics such\\u000a as importance analysis, dependent failures, disjoint events, and multistate systems will also be presented.

Liudong Xing; Suprasad V. Amari

142

Sharing A Labeled Tree  

Microsoft Academic Search

This paper introduces a way to share a labeled tree. For sharing a labeled tree, the Prufer code or a Prufer-like code of the tree is evaluated. Then, the terms of this code are modified by a function introduced to make shares, so that every term of the code can be deter- mined if and only if all the shares

Yasser A. Phoulady; Mahdi Behzadi; Hassan Taheri

143

Acacia Tree Ants  

NSDL National Science Digital Library

The phenomenon is the symbiotic relationship between the acacia ant and the swollen thorn acacia tree, shown in a 2:18 minute video. The ant provides protection for the tree against preying insects and other plants competing for sunlight, and the tree provides nourishment and shelter for the ant and the ants' larvae.

144

Minnesota's Forest Trees. Revised.  

ERIC Educational Resources Information Center

This bulletin describes 46 of the more common trees found in Minnesota's forests and windbreaks. The bulletin contains two tree keys, a summer key and a winter key, to help the reader identify these trees. Besides the two keys, the bulletin includes an introduction, instructions for key use, illustrations of leaf characteristics and twig…

Miles, William R.; Fuller, Bruce L.

145

RECURSIVE TREES Michael Drmota  

E-print Network

copies of ancient texts · convex hull algorithms · ... #12;Enumeration of Recursive Trees All recursiveRECURSIVE TREES Michael Drmota Institue of Discrete Mathematics and Geometry Vienna University School on GROWTH AND SHAPES, Paris, IHP, June 2­6, 2008 #12;Contents · Combinatorics on Recursive Trees

Drmota, Michael

146

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

147

The Wish Tree Project  

ERIC Educational Resources Information Center

This article describes the author's experience in implementing a Wish Tree project in her school in an effort to bring the school community together with a positive art-making experience during a potentially stressful time. The concept of a wish tree is simple: plant a tree; provide tags and pencils for writing wishes; and encourage everyone to…

Brooks, Sarah DeWitt

2010-01-01

148

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

149

Distributed Contour Trees  

SciTech Connect

Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-valued measurements. We study the parallel analysis of contour trees. After describing a particular representation of a contour tree, called local{global representation, we illustrate how di#11;erent problems that rely on contour trees can be solved in parallel with minimal communication.

Morozov, Dmitriy; Weber, Gunther H.

2014-03-31

150

Refining discordant gene trees  

PubMed Central

Background Evolutionary studies are complicated by discordance between gene trees and the species tree in which they evolved. Dealing with discordant trees often relies on comparison costs between gene and species trees, including the well-established Robinson-Foulds, gene duplication, and deep coalescence costs. While these costs have provided credible results for binary rooted gene trees, corresponding cost definitions for non-binary unrooted gene trees, which are frequently occurring in practice, are challenged by biological realism. Result We propose a natural extension of the well-established costs for comparing unrooted and non-binary gene trees with rooted binary species trees using a binary refinement model. For the duplication cost we describe an efficient algorithm that is based on a linear time reduction and also computes an optimal rooted binary refinement of the given gene tree. Finally, we show that similar reductions lead to solutions for computing the deep coalescence and the Robinson-Foulds costs. Conclusion Our binary refinement of Robinson-Foulds, gene duplication, and deep coalescence costs for unrooted and non-binary gene trees together with the linear time reductions provided here for computing these costs significantly extends the range of trees that can be incorporated into approaches dealing with discordance. PMID:25434729

2014-01-01

151

Balancing Minimum Spanning Trees and ShortestPath Trees  

E-print Network

Balancing Minimum Spanning Trees and Shortest­Path Trees Samir Khuller \\Lambda University and a minimum spanning tree. The algorithm provides a continuous trade­off: given the two trees and a fl ? 0 is at most 1 + p 2=fl times the weight of a minimum spanning tree. Our algorithm runs in linear time

Khuller, Samir

152

SIMPLY GENERATED TREES, CONDITIONED GALTONWATSON TREES, RANDOM ALLOCATIONS  

E-print Network

SIMPLY GENERATED TREES, CONDITIONED GALTON­WATSON TREES, RANDOM ALLOCATIONS AND CONDENSATION: EXTENDED ABSTRACT SVANTE JANSON 1. Simply generated trees and Galton­Watson trees We suppose that we nodes v in T, where d+(v) is the outdegree of v. Trees with such weights are called simply generated

Janson, Svante

153

SIMPLY GENERATED TREES, CONDITIONED GALTON--WATSON TREES, RANDOM ALLOCATIONS  

E-print Network

SIMPLY GENERATED TREES, CONDITIONED GALTON--WATSON TREES, RANDOM ALLOCATIONS AND CONDENSATION: EXTENDED ABSTRACT SVANTE JANSON 1. Simply generated trees and Galton--Watson trees We suppose that we of a finite rooted and ordered (a.k.a. plane) tree T by w(T ) := # v#T w d + (v) , (1.1) taking the product

Janson, Svante

154

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color-shifted complexes #12;Spanning trees

Duval, Art

155

From gene trees to species trees through a supertree approach  

E-print Network

From gene trees to species trees through a supertree approach Celine Scornavacca1,2, , Vincent Abstract. Gene trees are leaf-labeled trees inferred from molecular se- quences. Due to duplication events arising in genome evolution, gene trees usually have multiple copies of some labels, i.e. species

Paris-Sud XI, Université de

156

From Gene Trees to Species Trees through a Supertree Approach  

E-print Network

From Gene Trees to Species Trees through a Supertree Approach Celine Scornavacca1,2, , Vincent Abstract. Gene trees are leaf-labeled trees inferred from molecular se- quences. Due to duplication events arising in genome evolution, gene trees usually have multiple copies of some labels, i.e. species

Paris-Sud XI, Université de

157

Discordance of species trees with their most likely gene trees  

E-print Network

Discordance of species trees with their most likely gene trees James H. Degnan & Noah A. Rosenberg sort during speciation, gene trees may differ in topology from each other and from species trees find that for any species tree topology with five or more species, there exist branch lengths for which

Degnan, James

158

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes #12;Spanning trees of graphs

Duval, Art

159

Condensation in nongeneric trees  

E-print Network

We study nongeneric planar trees and prove the existence of a Gibbs measure on infinite trees obtained as a weak limit of the finite volume measures. It is shown that in the infinite volume limit there arises exactly one vertex of infinite degree and the rest of the tree is distributed like a subcritical Galton-Watson tree with mean offspring probability $mtrees in the thermodynamic limit and show it goes like $(1-m)N$ where $N$ is the size of the tree. These trees have infinite spectral dimension with probability one but the spectral dimension calculated from the ensemble average of the generating function for return probabilities is given by $2\\beta -2$ if the weight $w_n$ of a vertex of degree $n$ is asymptotic to $n^{-\\beta}$.

Thordur Jonsson; Sigurdur Orn Stefansson

2011-01-04

160

Friends of Trees  

NSDL National Science Digital Library

Based in Portland, Oregon, the Friends of Trees organization is dedicated to restoring urban forests around the country, with a particular emphasis on the Portland metropolitan area. As their Web site notes, "Trees are an essential part of the urban ecosystem. They help keep our water and air clean, prevent erosion, provide wildlife habitat, and make neighborhoods greener, more beautiful places to live." On the site, visitors can read about their ongoing planting activities and browse the newsletter they publish three times a year. For most visitors, the most helpful area of the site will be the Tree Resources section. Here, users can look through a fact sheet on the benefits of trees in urban environments, the care and maintenance of trees, and a large tree database.

161

In Focus: The Tree  

NSDL National Science Digital Library

In Focus: The Tree, is a Getty Museum exhibition of 41 images inspired by trees. On the exhibition's website visitors can see five images of trees, from Myoung Ho Lee, William Henry Fox Talbot, Darius Kinsey, Rhea Garen, and Simryn Gill, most accompanied by audio of curators or the artists discussing their work. Curator Fran�§oise Reynaud explains how early photographer Talbot may have created his 1842 salt print showing a bare oak tree in winter; living artist Rheas Garen discusses her picture "Treehouse", which shows a backyard where a tree dwarfs the house, taken with a large format camera in 1993. The associated book, The Tree in Photographs, compiled by Reynaud, includes eighty-one images selected from the Museum's permanent collection.

162

Bronchi, Bronchial Tree, & Lungs  

MedlinePLUS

... Larynx & Trachea Bronchi, Bronchial Tree, & Lungs Review Quiz Digestive System General Structure Regions of the Digestive System Mouth Pharynx & Esophagus Stomach Small & Large Intestine Accessory ...

163

Recursively Imputed Survival Trees  

PubMed Central

We propose recursively imputed survival tree (RIST) regression for right-censored data. This new nonparametric regression procedure uses a novel recursive imputation approach combined with extremely randomized trees that allows significantly better use of censored data than previous tree based methods, yielding improved model fit and reduced prediction error. The proposed method can also be viewed as a type of Monte Carlo EM algorithm which generates extra diversity in the tree-based fitting process. Simulation studies and data analyses demonstrate the superior performance of RIST compared to previous methods. PMID:23125470

Zhu, Ruoqing; Kosorok, Michael R.

2011-01-01

164

Species integrity in trees.  

PubMed

From California sequoia, to Australian eucalyptus, to the outstanding diversity of Amazonian forests, trees are fundamental to many processes in ecology and evolution. Trees define the communities that they inhabit, are host to a multiplicity of other organisms and can determine the ecological dynamics of other plants and animals. Trees are also at the heart of major patterns of biodiversity such as the latitudinal gradient of species diversity and thus are important systems for studying the origin of new plant species. Although the role of trees in community assembly and ecological succession is partially understood, the origin of tree diversity remains largely opaque. For instance, the relative importance of differing habitats and phenologies as barriers to hybridization between closely related species is still largely uncharacterized in trees. Consequently, we know very little about the origin of trees species and their integrity. Similarly, studies on the interplay between speciation and tree community assembly are in their infancy and so are studies on how processes like forest maturation modifies the context in which reproductive isolation evolves. In this issue of Molecular Ecology, Lindtke et al. (2014) and Lagache et al. (2014) overcome some traditional difficulties in studying mating systems and sexual isolation in the iconic oaks and poplars, providing novel insights about the integrity of tree species and on how ecology leads to variation in selection on reproductive isolation over time and space. PMID:25155715

Ortiz-Barrientos, Daniel; Baack, Eric J

2014-09-01

165

COMPONENT User's Guide Working with trees  

E-print Network

COMPONENT User's Guide Chapter 2 Working with trees This chapter gives you information on basic tree operations. The topics covered include: n reading and writing files of trees n editing trees n displaying and printing trees n selecting subsets of trees n pruning trees n rooting trees n computing tree

Page, Roderic

166

MUNICIPAL TREE PROGRAMS IN PENNSYLVANIA  

Microsoft Academic Search

Municipal tree programs were assessed in Pennsylvania through mail surveys. Pennsylvania has ap- proximately 378 tree programs of which 57% are implemented thrqugh shade tree commissions. Only 28% of Pennsylvania's citiqs and boroughs have tree programs. A high level of tree health exists in only 27% of the cities with programs. Only 28% of the programs have streettree inventories. Numbers

Eric C. Reeder; Henry D. Gerhold

1988-01-01

167

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.

American Forests

168

COMPONENT User's Guide Comparing trees  

E-print Network

COMPONENT User's Guide Chapter 5 Comparing trees This chapter describes the tree comparison measures available in COMPONENT, and the various ways you can compare trees using the program. Among the possible uses of tree comparison measures are: n comparing trees for the same taxa computed from different

Page, Roderic

169

TreeCmp: Comparison of Trees in Polynomial Time  

PubMed Central

When a phylogenetic reconstruction does not result in one tree but in several, tree metrics permit finding out how far the reconstructed trees are from one another. They also permit to assess the accuracy of a reconstruction if a true tree is known. TreeCmp implements eight metrics that can be calculated in polynomial time for arbitrary (not only bifurcating) trees: four for unrooted (Matching Split metric, which we have recently proposed, Robinson-Foulds, Path Difference, Quartet) and four for rooted trees (Matching Cluster, Robinson-Foulds cluster, Nodal Splitted and Triple). TreeCmp is the first implementation of Matching Split/Cluster metrics and the first efficient and convenient implementation of Nodal Splitted. It allows to compare relatively large trees. We provide an example of the application of TreeCmp to compare the accuracy of ten approaches to phylogenetic reconstruction with trees up to 5000 external nodes, using a measure of accuracy based on normalized similarity between trees.

Bogdanowicz, Damian; Giaro, Krzysztof; Wróbel, Borys

2012-01-01

170

Alternate Species Taxonomic Name: Rhus typhina `Laciniata'  

E-print Network

in a terminal cone-shaped fruit on the female plant. The fruit will persist into winter. Bark: Pale gray are produced in early summer. Plants are dioecious, meaning male and female plants are separate. This cutleaf cultivar selection is a female plant. Fruit: Bright crimson hairy drupes are clustered together

Hayden, Nancy J.

171

Balancing Minimum Spanning Trees and Shortest-Path Trees  

Microsoft Academic Search

We give a simple algorithm to find a spanning tree that simultaneously approxi- mates a shortest-path tree and a minimum spanning tree. The algorithm provides a continuous trade-off: given the two trees and a > 0, the algorithm returns a span- ning tree in which the distance between any vertex and the root of the shortest-path tree is at most

Samir Khuller; Penn State

1993-01-01

172

Tree height measurement protocol J Chave Page 1 Measuring tree height for tropical forest trees  

E-print Network

Tree height measurement protocol ­ J Chave Page 1 Measuring tree height for tropical forest trees Diversité Biologique Université Paul Sabatier 31000 Toulouse, France 1. Introduction Tree height is a fundamental geometrical variable for trees. Unfortunately, most measures are based on visual inspection

Chave, Jérôme

173

Apple Tree, NH Big Tree for May By Anne Krantz, NH Big Tree Team,  

E-print Network

Apple Tree, NH Big Tree for May By Anne Krantz, NH Big Tree Team, UNH Cooperative Extension The explosion of apple blossoms in May transforms the most gnarled old tree into a delicate cloud of beauty (1817-1862) in his essay "The Wild Apple Tree," described the blossoms perfectly: `The flowers

New Hampshire, University of

174

Rooting for Trees: Volunteers to Plant 20 Trees, Mark Tree Campus USA Honor  

E-print Network

Rooting for Trees: Volunteers to Plant 20 Trees, Mark Tree Campus USA Honor March 22, 2013 Event at The University of Texas at Austin will join the university urban forestry team in planting 20 large trees on the grounds of the Dell Pediatric Research Institute. Volunteers will also mulch more than 100 existing trees

Hofmann, Hans A.

175

Fragmentation of random trees  

NASA Astrophysics Data System (ADS)

We study fragmentation of a random recursive tree into a forest by repeated removal of nodes. The initial tree consists of N nodes and it is generated by sequential addition of nodes with each new node attaching to a randomly-selected existing node. As nodes are removed from the tree, one at a time, the tree dissolves into an ensemble of separate trees, namely, a forest. We study statistical properties of trees and nodes in this heterogeneous forest, and find that the fraction of remaining nodes m characterizes the system in the limit N\\to ? . We obtain analytically the size density {{? }s} of trees of size s. The size density has power-law tail {{? }s}˜ {{s}-? } with exponent ? =1+\\frac{1}{m}. Therefore, the tail becomes steeper as further nodes are removed, and the fragmentation process is unusual in that exponent ? increases continuously with time. We also extend our analysis to the case where nodes are added as well as removed, and obtain the asymptotic size density for growing trees.

Kalay, Z.; Ben-Naim, E.

2015-01-01

176

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

177

TRANSPLANTING SHADE TREES.  

ERIC Educational Resources Information Center

THIS RESOURCE MATERIAL FOR USE IN HIGH SCHOOL VOCATIONAL AGRICULTURE AND ADULT FARMER CLASSES WAS DESIGNED BY SUBJECT MATTER SPECIALISTS, TEACHER EDUCATORS, SUPERVISORS, AND TEACHERS. THE OBJECTIVE IS TO HELP SOLVE PROBLEMS IN TRANSPLANTING SHADE TREES. THE MAJOR SECTION TITLES ARE STATED AS PROBLEMS -- (1) HOW SHOULD I PREPARE A TREE FOR MOVING,…

Illinois Univ., Urbana. Coll. of Agriculture.

178

Oriented trees in digraphs  

E-print Network

Let f(k) be the smallest integer such that every f(k)-chromatic digraph contains every oriented tree of order k. Burr proved that f(k) ? (k?1) 2 and conjectured f(k) = 2n?2. In this paper, we give some sufficient conditions for an n-chromatic digraphs to contains some oriented tree. In particular

Louigi Addario-berry; Frédéric Havet; Cláudia Linhares Sales; Bruce Reed; Stéphan Thomassé

2011-01-01

179

Leonardo's Tree Theory  

NSDL National Science Digital Library

This activity focuses on Leonardo da Vinci's tree theory, which states that the cross-sectional area of a major limb is approximately equal to the cross-sectional areas of its two offshoot limbs. Students test this theory by collecting data from 10 trees and perform the mathematical calculations. In addition to data collection skills, this exercise strengthens problem solving skills.

Suzanne K. Werner

2003-03-01

180

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.

National Science Foundation

181

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.

2013-09-14

182

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

Richard Konicek-Moran

2008-04-01

183

Probabilistic Timed Behavior Trees  

Microsoft Academic Search

The Behavior Tree notation has been developed as a method for systematically and traceably capturing user requirements. In this paper we extend the notation with probabilistic behaviour, so that relia- bility, performance, and other dependability properties can be expressed. The semantics of probabilistic timed Behavior Trees is given by mapping them to probabilistic timed automata. We gain advantages for require-

Robert Colvin; Lars Grunske; Kirsten Winter

2007-01-01

184

CSI for Trees  

NSDL National Science Digital Library

The circles and patterns in a tree's stem tell a story, but that story can be a mystery. Interpreting the story of tree rings provides a way to heighten the natural curiosity of students and help them gain insight into the interaction of elements in the e

Darrin L. Rubino

2009-10-01

185

Trees in Our Lives.  

ERIC Educational Resources Information Center

Provides: (1) background information on how trees have influenced human history and how trees affect people today; (2) four activities dealing with these topics; and (3) a ready-to-copy page related to paper and plastics. Activities include an objective, recommended age level(s), subject area(s), list of materials needed, and procedures. (JN)

NatureScope, 1986

1986-01-01

186

CSI for Trees  

ERIC Educational Resources Information Center

The circles and patterns in a tree's stem tell a story, but that story can be a mystery. Interpreting the story of tree rings provides a way to heighten the natural curiosity of students and help them gain insight into the interaction of elements in the environment. It also represents a wonderful opportunity to incorporate the nature of science.…

Rubino, Darrin L.; Hanson, Deborah

2009-01-01

187

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

Richard Konicek-Moran

2009-04-01

188

Tree Diagrams and Probability  

NSDL National Science Digital Library

This lesson is designed to develop students' ability to create tree diagrams and figure probabilities of events based on those diagrams. This lesson provides links to discussions and activities related to tree diagrams as well as suggested ways to work them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2011-01-20

189

Climate change & street trees project  

E-print Network

Climate change & street trees project Social Research Report The social and cultural values, and governance, of street trees Norman Dandy March 2010 #12;Contents Summary .................................................................................................4 1.1 What is a `street tree

190

Verticillium Wilt of Shade Trees  

E-print Network

Ginkgo Mountain ash Walnut Hackberry Mulberry Willow Hawthorn Oak Yew Hickory Pawpaw Zelkova Verticillium Sassafras Boxwood Horse chestnut Serviceberry Brambles Japanese pagoda tree Smoke tree Buckeye Lilac Sumac

191

Ash Tree Identification Key Ash Tree Characteristics  

E-print Network

berries Walnut, Hickory, Mountain-Ash: alternate branching #12;Identifying Emerald Ash Borer what to do if you think you have the ash-killing Emerald Ash Borer (EAB) in your ash tree Verify the signs of EAB: 1/8" "D" shaped "S" shaped tunnels small, 3/4" metallic green beetles 1/8 D shaped exit holes

Walter, M.Todd

192

Language trees not equal gene trees.  

PubMed

Darwin saw similarities between the evolution of species and the evolution of languages, and it is now widely accepted that similarities between related languages can often be interpreted in terms of a bifurcating descent history ('phylogenesis'). Such interpretations are supported when the distributions of shared and unshared traits (for example, in terms of etymological roots for elements of basic vocabulary) are analysed using tree-building techniques and found to be well-explained by a phylogenetic model. In this article, we question the demographic assumption which is sometimes made when a tree-building approach has been taken to a set of cultures or languages, namely that the resulting tree is also representative of a bifurcating population history. Using historical census data relating to Gaelic- and English-speaking inhabitants of Sutherland (Highland Scotland), we have explored the dynamics of language death due to language shift, representing the extreme case of lack of congruence between the genetic and the culture-historical processes. Such cases highlight the important role of selective cultural migration (or shifting between branches) in determining the extinction rates of different languages on such trees. PMID:20532998

Steele, James; Kandler, Anne

2010-09-01

193

LVIS Tree Height Cross Section (tree texture)  

NSDL National Science Digital Library

This animation starts with a false-color map of tree heights north of San Jose, Costa Rica, and changes to a close-up 3D cut-away of a section of the forest with simulated green canopy. Data from LVIS observations taken in March, 1998.

Randall Jones

1999-09-17

194

Week 10: Consensus trees, tree distances, tests of tree March, 2010  

E-print Network

­ p.11/40 #12;A consensus subtree F C A B G DFCA BDE F AB D E Week 10: Consensus trees, tree distances, tests of tree shape ­ p.12/40 #12;A consensus subtree F C A B G DFCA BDE F AB D E Week 10: Consensus trees, tree distances, tests of tree shape ­ p.13/40 #12;A consensus subtree F C A B G DFCA BDE F AB D E

Borenstein, Elhanan

195

binary-tree B-tree Hashing Space-Filling based location  

E-print Network

#12;#12;#12;binary-tree B-tree Hashing Space-Filling Quad-tree based location keys R -tree+ PLOP Hashing EXCELL R-tree Grid-files kd-tree kd-B-treeBD-tree 1984 1985 1986 1987 1988 1989 1990 1991 1992 LSD-tree GBD-tree skd-tree Packed R-tree multi-level GF Cell-tree hB-tree R-files GGF mkd-tree 4d-tree 4d-tree

Ooi, Beng Chin

196

Lazy decision trees  

SciTech Connect

Lazy learning algorithms, exemplified by nearest-neighbor algorithms, do not induce a concise hypothesis from a given training set; the inductive process is delayed until a test instance is given. Algorithms for constructing decision trees, such as C4.5, ID3, and CART create a single {open_quotes}best{close_quotes} decision tree during the training phase, and this tree is then used to classify test instances. The tests at the nodes of the constructed tree are good on average, but there may be better tests for classifying a specific instance. We propose a lazy decision tree algorithm-LazyDT-that conceptually constructs the {open_quotes}best{close_quote} decision tree for each test instance. In practice, only a path needs to be constructed, and a caching scheme makes the algorithm fast. The algorithm is robust with respect to missing values without resorting to the complicated methods usually seen in induction of decision trees. Experiments on real and artificial problems are presented.

Friedman, J.H.; Yun, Yeogirl [Stanford Univ., CA (United States); Kohavi, R. [Silicon Graphics, Inc., Mountain View, CA (United States)

1996-12-31

197

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.

198

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

199

44 TREE CARE INDUSTRY -MARCH 2002 Tree&Landscape  

E-print Network

44 TREE CARE INDUSTRY - MARCH 2002 Tree&Landscape 44 II nstallation of underground irrigation green in more ways than one. From keeping trees healthy to providing a viable source of income to their clients. Improved soil con- ditions for tree growth can be achieved using irrigation, and state

Schweik, Charles M.

200

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Mathematics Seminar Reed College April 28, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

201

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 of Kansas Discrete CATS seminar University of Kentucky March 30, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

202

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Critical group of graphs Critical group of simplicial complexes Spanning trees and the critical group of simplicial complexes Art Duval1 Mathematics Colloquium New Mexico State University October 20, 2011 Duval, Klivans, Martin Spanning trees

Duval, Art

203

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 of Mississippi March 2, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful

Duval, Art

204

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Complete colorful complexes Weighted spanning tree enumerators of complete colorful complexes Ghodratollah Aalipour1,2 Art Duval1 1 April 21, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of complete colorful complexes

Duval, Art

205

Discordance of Species Trees with Their Most Likely Gene Trees  

E-print Network

Discordance of Species Trees with Their Most Likely Gene Trees James H. Degnan1 , Noah A. Rosenberg way in which lineages sort during speciation, gene trees may differ in topology from each other and from species trees. Surprisingly, assuming that genetic lineages follow a coalescent model of within

Rosenberg, Noah

206

Spanning trees of graphs Spanning trees of simplicial complexes  

E-print Network

Spanning trees of graphs Spanning trees of simplicial complexes Color-shifted complexes Weighted spanning tree enumerators of color-shifted complexes Ghodratollah Aalipour1,2 Art Duval1 1University in St. Louis October 20, 2013 Ghodratollah Aalipour, Art Duval Spanning tree enumerators of color

Duval, Art

207

Discordance of Species Trees with Their Most Likely Gene Trees  

Microsoft Academic Search

Because of the stochastic way in which lineages sort during speciation, gene trees may differ in topology from each other and from species trees. Surprisingly, assuming that genetic lineages follow a coalescent model of within-species evolution, we find that for any species tree topology with five or more species, there exist branch lengths for which gene tree discordance is so

James H. Degnan; Noah A. Rosenberg

2006-01-01

208

Peach Tree Pruning.  

E-print Network

removes the terminal portion of shoots, stimulates regrowth near the cut and is the most invigorating type of cut. It induces branching at spe cific points such as establishing scaffolds in young trees. However, heading has the greatest effect... are small to reduce regrowth. Train scaffolds to a 45? angle in the early years to minimize the need for severe bench cuts later (figure 2). Pruning Newly Set Trees Prune newly planted trees immediately after plant ing. Use a heading cut 24 to 30...

Lyons, Calvin G.

1986-01-01

209

What Tree Is It?  

NSDL National Science Digital Library

This online tree-identification tool was created by the Ohio Public Library Information Network (OPLIN) and the Ohio Historical Society (OHS). Users work their way through qualities of leaves and fruits, selecting images that more closely resemble their sample. Fact pages provide instruction on fruit and leaf structures and terminology, close-up photographs of seeds, fruits, bark, leaves, or other plant parts useful in identifying the tree, as well as a picture of the full tree and information about its habitat, history, and structure.

210

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

211

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

212

TreeBase  

NSDL National Science Digital Library

TreeBase (last mentioned in the October 30, 1998 Scout Report) is a database of phylogenetic information sponsored by Harvard University Herbaria, Leiden University EEW, and the University of California, Davis. The site stores phylogenetic trees and the data matrices used to generate them from published research papers and currently includes 1098 authors, 614 studies, 1704 trees, and 21456 taxa (roughly three times more data than the Scout Report first review in 1998). The searchable database takes a little time getting used to, but the resulting information is valuable.

213

Minimum spanning trees for tree metrics: abridgements and adjustments  

Microsoft Academic Search

Two properties of tree metrics are already known in the literature: tree metrics on a setX withn elements have 2n?3 degrees of freedom; a tree metric has Robinson form with regard to its minimum spanning tree (MST), or to any such MST\\u000a if several of them exist. Starting from these results, we prove that a tree metrict is entirely defined

Bruno Leclerc

1995-01-01

214

Structural Equation Model Trees  

PubMed Central

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 structures that separate a data set recursively into subsets with significantly different parameter estimates in a SEM. SEM Trees provide means for finding covariates and covariate interactions that predict differences in structural parameters in observed as well as in latent space and facilitate theory-guided exploration of empirical data. We describe the methodology, discuss theoretical and practical implications, and demonstrate applications to a factor model and a linear growth curve model. PMID:22984789

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

2015-01-01

215

Construct a phylogenetic tree  

NSDL National Science Digital Library

This web page will construct a phylogenetic tree of the creatures you select below. It will use the protein sequences of the protein cytochrome c from each of these organisms to construct the tree. Select the desired creatures from the lists below. To select more than one in the same list, hold down the apple key (on Macs); the control key (on PCs); on the Suns, you just click. If you want to clear your selections and start over, click the "Clear all selections" button. You must also choose one and only one outgroup organism so that your tree will have a root. This is especially important for the parsimony analysis. The outgroup organism should not be closely related to the other organisms. When you have made the selections you want, click the "calculate tree" button. Your request will then be processed. This may take a while, so please be patient.

Brian White

2012-06-28

216

Leonardo's Tree Theory.  

ERIC Educational Resources Information Center

Describes a series of activities exploring Leonardo da Vinci's tree theory that are designed to strengthen 8th grade students' data collection and problem solving skills in physical science classes. (KHR)

Werner, Suzanne K.

2003-01-01

217

Generalized constructive tree weights  

SciTech Connect

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, E-mail: vincent.rivasseau@th.u-psud.fr, E-mail: adrian.tanasa@ens-lyon.org [LPT, CNRS UMR 8627, Univ. Paris 11, 91405 Orsay Cedex, France and Perimeter Institute for Theoretical Physics, 31 Caroline St. N, Ontario N2L 2Y5, Waterloo (Canada)] [LPT, CNRS UMR 8627, Univ. Paris 11, 91405 Orsay Cedex, France and Perimeter Institute for Theoretical Physics, 31 Caroline St. N, Ontario N2L 2Y5, Waterloo (Canada); Tanasa, Adrian, E-mail: vincent.rivasseau@th.u-psud.fr, E-mail: adrian.tanasa@ens-lyon.org [Université Paris 13, Sorbonne Paris Cité, 99, Avenue Jean-Baptiste Clément LIPN, Institut Galilée, CNRS UMR 7030, F-93430 Villetaneuse, France and Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125 Magurele (Romania)] [Université Paris 13, Sorbonne Paris Cité, 99, Avenue Jean-Baptiste Clément LIPN, Institut Galilée, CNRS UMR 7030, F-93430 Villetaneuse, France and Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125 Magurele (Romania)

2014-04-15

218

Combining Binary Search Trees  

E-print Network

We present a general transformation for combining a constant number of binary search tree data structures (BSTs) into a single BST whose running time is within a constant factor of the minimum of any “well-behaved” bound ...

Demaine, Erik D.

219

Tree-bank grammars  

SciTech Connect

By a {open_quotes}tree-bank grammar{close_quotes} we mean a context-free grammar created by reading the production rules directly from hand-parsed sentences in a tree bank. Common wisdom has it that such grammars do not perform well, though we know of no published data on the issue. The primary purpose of this paper is to show that the common wisdom is wrong. In particular, we present results on a tree-bank grammar based on the Penn Wall Street Journal tree bank. To the best of our knowledge, this grammar outperforms all other non-word-based statistical parsers/grammars on this corpus. That is, it outperforms parsers that consider the input as a string of tags and ignore the actual words of the corpus.

Charniak, E. [Brown Univ., Providence, RI (United States)

1996-12-31

220

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

221

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.

2007-08-09

222

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

223

ENERGY SAVINGS WITH TREES1  

Microsoft Academic Search

In conventional buildings, trees increase, decrease, or have little effect on energy use depending on general climate, building type, tree species, and tree location. Tree arrangements that save energy provide shade primarily for east and west walls and roofs and wind protection from the direction of prevailing winter winds. Particularly for buildings specially designed to use solar energy and those

Gordon M. Heisler

1986-01-01

224

Planar Bichromatic Minimum Spanning Trees  

E-print Network

Planar Bichromatic Minimum Spanning Trees Magdalene G. Borgelt Marc van Kreveld Maarten L Bichromatic Minimum Spanning Trees Magdalene G. Borgelt1 Marc van Kreveld2 Maarten L¨offler2 Jun Luo2 Damian points in the plane, a planar bichromatic minimum spanning tree is the shortest possible spanning tree

Utrecht, Universiteit

225

The Minimum Labeling Spanning Trees  

Microsoft Academic Search

One of the fundamental problems in graph theory is to compute a minimum weight spanning tree. In this paper, a variant of spanning trees, called the minimum labeling spanning tree, is studied. The purpose is to find a spanning tree that tries to use edges that are as similar as possible. Giving each edge a label, the minimum labeling spanning

Ruay-Shiung Chang; Shing-jiuan Leu

1997-01-01

226

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.

227

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

228

COMPONENT User's Guide Consensus trees  

E-print Network

COMPONENT User's Guide Chapter 4 Consensus trees Consensus trees are a convenient way to summarise the agreement between two or more trees. This chapter describes the consensus methods available in COMPONENT subtree (Kubicka et al, 1992; also called the common pruned tree [Finden and Gordon, 1985]). This method

Page, Roderic

229

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.

Robert S. Cole

230

A future with broadleaved trees  

E-print Network

A future with broadleaved trees A strategy for the Improvement of broadleaved trees in Britain and Ireland 2013-2025 Supported by #12;2 A future with broAdleAved trees Many people and organisations from and highlights areas where we believe further consideration is required. Future Trees Trust, Earth Trust

231

How Trees Can Save Energy.  

ERIC Educational Resources Information Center

This document might easily have been called "How To Use Trees To Save Energy". It presents the energy saving advantages of landscaping the home and community with trees. The discussion includes: (1) landscaping advice to obtain the benefits of tree shade; (2) the heat island phenomenon in cities; (3) how and where to properly plant trees for…

Fazio, James R., Ed.

1991-01-01

232

TREES of SCa Public Service of Clemson University S.C. Champion Tree Nomination Form  

E-print Network

CHAMPION TREES of SCa Public Service of Clemson University S.C. Champion Tree Nomination Form Today's date: ___________________________ Scientific tree name: ________________________________________________ Common tree name: _________________________________________________ Group

Duchowski, Andrew T.

233

Core Based Trees (CBT)  

Microsoft Academic Search

One of the central problems in one-to-many wide-area communications is forming the delivery tree - the collection of nodes and links that a multicast packet traverses. Significant problems remain to be solved in the area of multicast tree formation, the problem of scaling being paramount among these.In this paper we show how the current IP multicast architecture scales poorly (by

Tony Ballardie; Paul Francis; Jon Crowcroft

1993-01-01

234

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

235

The Ubiquitous B-Tree  

Microsoft Academic Search

B-trees have become, de facto, a standard for file organization. File indexes of users, dedicated database systems, and general-purpose access methods have all been proposed and implemented using B-trees. This paper reviews B-trees and shows why they have been so successful. It discusses the major variations of the B-tree, especially the W-tree, contrasting the relative merits and costs of each

Douglas E. Comer

1979-01-01

236

Tree manipulation experiment  

NASA Astrophysics Data System (ADS)

Some forest operations such as thinning and harvesting management could cause changes in N cycling and N2O emission from soils, since thinning and harvesting managements are accompanied with changes in aboveground environments such as an increase of slash falling and solar radiation on the forest floor. However, a considerable uncertainty exists in effects of thinning and harvesting on N2O fluxes regarding changes in belowground environments by cutting trees. To focus on the effect of changes in belowground environments on the N2O emissions from soils, we conducted a tree manipulation experiment in Japanese cedar (Cryptomeria japonica) stand without soil compaction and slash falling near the chambers and measured N2O flux at 50 cm and 150 cm distances from the tree trunk (stump) before and after cutting. We targeted 5 trees for the manipulation and established the measurement chambers to the 4 directions around each targeted tree relative to upper slope (upper, left, right, lower positions). We evaluated the effect of logging on the emission by using hierarchical Bayesian model. HB model can evaluate the variability in observed data and their uncertainties in the estimation with various probability distributions. Moreover, the HB model can easily accommodate the non-linear relationship among the N2O emissions and the environmental factors, and explicitly take non-independent data (nested structure of data) for the estimation into account by using random effects in the model. Our results showed tree cutting stimulated N2O emission from soils, and also that the increase of N2O flux depended on the distance from the trunk (stump): the increase of N2O flux at 50 cm from the trunk (stump) was greater than that of 150 cm from the trunk. The posterior simulation of the HB model indicated that the stimulation of N2O emission by tree cut- ting could reach up to 200 cm in our experimental plot. By tree cutting, the estimated N2O emission at 0-40 cm from the trunk doubled (the % increase of N2O emission; 54% to 213%; 95% C.I.) condition when soil temperature was 25oC and WFPS was 60%. The posterior simulation of the model estimated that 10% logging caused a 20% (15% to 24%; 95% CI) increase N2O emission in our study site (2000 trees ha-1) for the only tree cutting effects during the measurement period (about 160 day). On the basis of our findings, the belowground environmental changes by logging management would considerably contribute the stimulation of N2O emission.

Nishina, K.; Takenaka, C.; Ishizuka, S.; Hashimoto, S.; Yagai, Y.

2012-12-01

237

Laccase from Sycamore Maple (Acer pseudoplatanus) Polymerizes Monolignols  

PubMed Central

Current understanding of the final oxidative steps leading to lignin deposition in trees and other higher plants is limited with respect to what enzymes are involved, where they are localized, how they are transported, and what factors regulate them. With the use of cell suspension cultures of sycamore maple (Acer pseudoplatanus), an in-depth study of laccase, one of the oxidative enzymes possibly responsible for catalyzing the dehydrogenative polymerization of monolignols in the extracellular matrix, was undertaken. The time course for secretion of laccase into suspension culture medium was determined with respect to age and mass of the cells. Laccase was completely separated from peroxidase activity by hydrophobic interaction column chromatography, and its purity was assessed with different types of gel electrophoresis (isoelectric focusing-, native-, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Amino acid and glycosyl analyses of the purified enzyme were compared with those reported from previous studies of plant and fungal laccases. The specific activity of laccase toward several common substrates, including monolignols, was determined. Unlike a laccase purified from the Japanese lacquer tree (Rhus vernicifera), laccase from sycamore maple oxidized sinapyl, coniferyl, and p-coumaryl alcohols to form water-insoluble polymers (dehydrogenation polymers). ImagesFigure 3 PMID:16668984

Sterjiades, Raja; Dean, Jeffrey F. D.; Eriksson, Karl-Erik L.

1992-01-01

238

The Inference of Gene Trees with Species Trees  

PubMed Central

This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree–species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree–species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution. PMID:25070970

Szöll?si, Gergely J.; Tannier, Eric; Daubin, Vincent; Boussau, Bastien

2015-01-01

239

The inference of gene trees with species trees.  

PubMed

This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree-species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree-species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution. PMID:25070970

Szöll?si, Gergely J; Tannier, Eric; Daubin, Vincent; Boussau, Bastien

2015-01-01

240

Nearest tree Always go to the closest  

E-print Network

Nearest tree Always go to the closest tree Largest tree Always go to the tree with the most apples Optimal 1-step forager Maximize rate (= ratio of apples to travel time), but only consider one tree at a time # apples travel time Optimal 2-, 3-step forager Maximize rate over 2-tree (or 3-tree) paths

241

In this chapter we study infinite trees. The main things we look at are Konig's tree theorem, Aronszajn trees, and Suslin trees.  

E-print Network

14. Trees In this chapter we study infinite trees. The main things we look at are K¨onig's tree theorem, Aronszajn trees, and Suslin trees. A tree is a partially ordered set (T, t T, the set {s T : s tree

Monk, Don

242

In this chapter we study infinite trees. The main things we look at are Konig's tree theorem, Aronszajn trees, and Suslin trees.  

E-print Network

8. Trees In this chapter we study infinite trees. The main things we look at are K¨onig's tree theorem, Aronszajn trees, and Suslin trees. A tree is a partially ordered set (T, t T, the set {s T : s tree

Monk, Don

243

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.

244

Trees: Recorders of Climate Change  

NSDL National Science Digital Library

In this activity, learners are introduced to tree rings by examining a cross section of a tree, also known as a “tree cookie.” They discover how tree age can be determined by studying the rings and how ring thickness can be used to deduce times of optimal growing conditions. Next they investigate simulated tree rings by applying the scientific method to explore how climatic conditions varied during the Little Ice Age. Use this activity to begin discussions on global warming and climate change. This lesson guide includes background information and handouts. Note: cost of materials does not include cost of purchasing "tree cookies."

2012-03-30

245

Predictive Classification Trees  

NASA Astrophysics Data System (ADS)

CART (Breiman et al., Classification and Regression Trees, Chapman and Hall, New York, 1984) and (exhaustive) CHAID (Kass, Appl Stat 29:119-127, 1980) figure prominently among the procedures actually used in data based management, etc. CART is a well-established procedure that produces binary trees. CHAID, in contrast, admits multiple splittings, a feature that allows to exploit the splitting variable more extensively. On the other hand, that procedure depends on premises that are questionable in practical applications. This can be put down to the fact that CHAID relies on simultaneous Chi-Square- resp. F-tests. The null-distribution of the second test statistic, for instance, relies on the normality assumption that is not plausible in a data mining context. Moreover, none of these procedures - as implemented in SPSS, for instance - take ordinal dependent variables into account. In the paper we suggest an alternative tree-algorithm that: Requires explanatory categorical variables

Dlugosz, Stephan; Müller-Funk, Ulrich

246

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,” 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.

247

Tree of Life  

NSDL National Science Digital Library

This fun Web site is part of OLogy, where kids can collect virtual trading cards and create projects with them. Here, they explore the Tree of Life cladogram. The site begins with a brief explanation of cladograms and how the Tree of Life shows the relationship of all living things on Earth. A cladogram of fruit is used to demonstrate on a small scale how scientists use this tool to understand how things are similar and different. A portion of the Tree of Life cladogram is included, showing true bacteria, arthropods, mammals, and 11 other important groups of species. Students can mouse over the branching points to see what the subsets have in common. The site also includes a pie chart view that compares the relative size of the most important groups of species. Students can click on each group to learn its characteristics, known species, size range, and other important details.

248

The Probability of Topological Concordance of Gene Trees and Species Trees  

Microsoft Academic Search

The concordance of gene trees and species trees is reconsidered in detail, allowing for samples of arbitrary size to be taken from the species. A sense of concordance for gene tree and species tree topologies is clarified, such that if the “collapsed gene tree” produced by a gene tree has the same topology as the species tree, the gene tree

Noah A. Rosenberg

2002-01-01

249

Trees from the Seas  

NSDL National Science Digital Library

This project provides a case study introducing students to patterns of relationships and evolution among economically important dinoflagellates, the causative agents of red tides. Using nucleotide sequences, students build a tree of relationships among dinoflagellate taxa. They use their tree (along with phylogenetic hypotheses derived from the literature) to explore the evolution of morphological and/or ecological characters in dinoflagellates. As broader applications, students learn to compare and evaluate hypotheses of evolutionary relationships. Additionally, because the case study focuses on dinoflagellates that have evolved toxicity, it can be used to further explore the biological and economic impacts of red tides.

Marsha Timmerman (La Salle University; )

2007-06-17

250

A celestial Christmas tree  

NASA Astrophysics Data System (ADS)

Having finished decorating your terrestrial Christmas tree this year, you may care to step outside and view a celestial one. Well placed in the December night sky in the often overlooked but very rewarding constellation of Monoceros, NGC 2264, called the Christmas Tree by the American astronomer and writer Leland S. Copeland, lies due south around 1 a.m. in mid-December at an altitude of 50°. The cluster lies amid a vast area of nebulosity, well captured in the image by Gordon Rogers on the cover of this Journal.

Moore, S.

2006-12-01

251

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.

John Pratte

252

Tree weight estimates for small-sized trees  

Microsoft Academic Search

This note describes a method for developing accurate equations for determining oven-dried weights of main-stem wood and total (main-stem wood + bark + brench-wood) weight yields of small-sized trees. Separate oven-dried, main-stem wood and total tree weight equations for ages 1-4 for hybrid poplar trees are presented. A comparative summary of selected 4-year-old trees calculated from volume and 3 specific

T. W. Bowersox; W. K. Murphey

1975-01-01

253

TREE LILAC CULTIVARS TESTED AS STREET TREES: INITIAL RESULTS  

Microsoft Academic Search

Three Japanese tree lilac (Syringa reticulata) culti- vars, 2 each in 11 communities, were planted for evaluation as street trees. Cooperators in the Municipal Tree Restora- tion Program using standardized methods measured them annually for 3 years, and periodically afterwards. 'Ivory Silk', 'Regent', and 'Summer Snow' performed well at all locations. All 3 cultivars grew slowly initially, and their foli-

Henry D. Gerhold

1999-01-01

254

Every Tree For Itself A Project Learning Tree Activity  

E-print Network

) Explain that each ring on the tree cookie represents a year of growth. 2) Have the students count the growth rings and report how old the tree was when it was cut down. 3) Give each student a paper plate and crayons and have them draw their own tree cookie. 4) Each student's cookie should have a ring for each

Acton, Scott

255

Hardware-based Reliability Tree (HRT) for fault tree analysis  

Microsoft Academic Search

Reliability analysis of critical systems is performed using fault trees. Fault trees are then converted to their equivalent Binary Decision Diagram, Cut Set, Markov Chain or Bayesian Network. These approaches however are complex and time consuming if a continuous time reliability curve is aimed, particularly for large systems. This paper introduces Hardware-based Reliability Tree (HRT). The HRT can be implemented

Amir Rajabzadeh; Mohammad S. Jahangiry

2010-01-01

256

ENVIRONMENTAL ARBORICULTURE, TREE ECOLOGY AND VETERAN TREE MANAGEMENT  

Microsoft Academic Search

The appreciation and management of veteran trees has been transformed in recent years by the activity of the Ancient Tree Forum (ATF). This is a UK initiative, which has brought attention to the quality and condition of the living heritage reflected in the great number of ancient tree sites found in the British Isles, which are among the finest in

Neville Fay

2002-01-01

257

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.

Stu Cork

2014-01-01

258

4-H SEEDLING TREE PROGRAM  

E-print Network

, erosion control, wind and sound barriers, wild- life habitats, and other conservation purposes. Jefferson2013 4-H SEEDLING TREE PROGRAM Seedling trees for conservation planting in the spring of 2013

259

Classify the trees/Leaves  

NSDL National Science Digital Library

This activity is a field investigation where students gather leaves from various trees on school property, interpret findings, name tree and leaves, journal activity and develop a new "aha" for nature!

Mary Walsh

260

Can These Trees Be Saved?  

E-print Network

This publication explains how to determine whether a storm-damaged tree can be saved. If the damage is not severe, most trees will recover in time. Helpful illustrations depict different levels of damage....

Taylor, Eric; Foster, C. Darwin

2005-10-19

261

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....

262

A Universal Phylogenetic Tree.  

ERIC Educational Resources Information Center

Presents a universal phylogenetic tree suitable for use in high school and college-level biology classrooms. Illustrates the antiquity of life and that all life is related, even if it dates back 3.5 billion years. Reflects important evolutionary relationships and provides an exciting way to learn about the history of life. (SAH)

Offner, Susan

2001-01-01

263

Tree Fertilization Soil Analysis  

E-print Network

Tree Fertilization #12;Soil Analysis vs. Foliar Analysis #12;Macronutrients N P K Mg S Ca Micronutrients Fe Mn Zn Mo Cu Cl B #12;Complete fertilizer N P K #12;Fertilizer Analysis Percentages of N P K #12;ANSI A-300 Fertilizer Standard Standards are used to develop contract specifications. Fertilize

264

The Sacred Tree.  

ERIC Educational Resources Information Center

Designed as a text for high school students and adults, this illustrated book presents ethical concepts and teachings of Native societies throughout North America concerning the nature and possibilities of human existence. The final component of a course in self-discovery and development, the book begins with the legend of the "Sacred Tree"…

Lethbridge Univ. (Alberta).

265

Induction of decision trees  

Microsoft Academic Search

The technology for building knowledge-based systems by inductive inference from examples has been demonstrated successfully in several practical applications. This paper summarizes an approach to synthesizing decision trees that has been used in a variety of systems, and it describes one such system, ID3, in detail. Results from recent studies show ways in which the methodology can be modified to

J. Ross Quinlan

1986-01-01

266

Phylogenics & Tree-Thinking  

ERIC Educational Resources Information Center

Phylogenetic trees, which are depictions of the inferred evolutionary relationships among a set of species, now permeate almost all branches of biology and are appearing in increasing numbers in biology textbooks. While few state standards explicitly require knowledge of phylogenetics, most require some knowledge of evolutionary biology, and many…

Baum, David A.; Offner, Susan

2008-01-01

267

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.

2012-08-03

268

Tree-Ties.  

ERIC Educational Resources Information Center

Created to help students understand how plants were used for food, for medicine, and for arts and crafts among the Ojibwe (Chippewa) Indians, the game Tree-Ties combines earth and social sciences within a specific culture. The game requires mutual respect, understanding, and agreement to succeed. Sounding like the word "treaties", the title is a…

Gresczyk, Rick

269

Arbutus unedo, Strawberry Tree  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Encylopedia of Fruit and Nuts is designed as a research reference source on temperate and tropical fruit and nut crops. Strawberry tree or madrone is native to the Mediterranean region of southern Europe (Arbutus unedo L., Ericaceae) with a relict population in Ireland, as well as in North Ameri...

270

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

271

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.

272

Reconstructing trees from subtree weights  

Microsoft Academic Search

The tree-metric theorem provides a necessary and sufficient condi- tion for a dissimilarity matrix to be a tree metric, and has served as the foundation for numerous distance-based reconstruction methods in phy- logenetics. Our main result is an extension of the tree-metric theorem to more general dissimilarity maps. In particular, we show that a tree with n leaves is reconstructible

Lior Pachter; David E Speyer

2004-01-01

273

Generating trees for permutations avoiding generalized patterns  

E-print Network

Generating trees for permutations avoiding generalized patterns Sergi Elizalde Dartmouth College Permutation Patterns 2006, Reykjavik Permutation Patterns 2006, Reykjavik ­ p.1 #12;Generating trees patterns Generating trees Rightward generating trees Enumeration of permutations avoiding generalized

Elizalde, Sergi

274

Learning Deterministically Recognizable Tree Series  

Microsoft Academic Search

We devise a learning algorithm for deterministically rec- ognizable tree series where the weights are taken from a commutative group. For this, we use an adaptation of the minimal adequate teacher model that was originally introduced by Angluin. The algorithm runs in polynomial time and constructs the unique minimal deterministic bottom-up finite state weighted tree automaton that recognizes the tree

Frank Drewes; Heiko Vogler

2007-01-01

275

Compositions of Tree Series Transformations  

E-print Network

, 19, 4]. So far, the latter are applied in code selection and tree pattern matching [13, 3]. Weighted. The probability is derived from the evidence found in the tree bank. Now the transformation stage translates series; i. e., mappings from a set of trees into a semiring. The translation stage can then be seen

Reyle, Uwe

276

The Hopi Fruit Tree Book.  

ERIC Educational Resources Information Center

Referring as often as possible to traditional Hopi practices and to materials readily available on the reservation, the illustrated booklet provides information on the care and maintenance of young fruit trees. An introduction to fruit trees explains the special characteristics of new trees, e.g., grafting, planting pits, and watering. The…

Nyhuis, Jane

277

Transversals in Trees Victor Campos  

E-print Network

, Belgium, perouz.taslakian@ulb.ac.be 1 #12;Harary and Schwenk [9] call a caterpillar a tree (an unrooted will call a caterpillar any rooted tree where removal of all leaves produces a rooted tree with precisely one leaf. By a full caterpillar of degree d, we will mean a caterpillar where each internal node

Devroye, Luc

278

Qualitative Tree Languages Arnaud Carayol  

E-print Network

Qualitative Tree Languages Arnaud Carayol LIGM (Univ. Paris Est & CNRS) Arnaud) Olivier.Serre@liafa.jussieu.fr Abstract--We study finite automata running over infinite binary trees) of non-accepting branches. In this qualitative setting, a tree is accepted by the automaton

Paris-Sud XI, Université de

279

The Re-Think Tree.  

ERIC Educational Resources Information Center

The Re-Think Tree is a simple framework to help individuals assess and improve their behaviors related to environmental issues. The branches of the tree in order of priority are refuse, reduce, re-use, and recycle. Roots of the tree include such things as public opinion, education, and watchdog groups. (KS)

Gear, Jim

1993-01-01

280

Selecting Trees for Community Landscapes  

Microsoft Academic Search

Selecting the most appropriate trees for various kinds of planting sites is crucial for the success of a municipal tree program. A properly selected tree will appreciate in value for a long time and will be cherished by many people. Conversely, an improper choice might soon become unhealthy or die. Even worse, problems could appear years later when a remedy

Henry D. Gerhold; William Porter

281

Building up rhetorical structure trees  

SciTech Connect

I use the distinction between the nuclei and the satellites that pertain to discourse relations to introduce a compositionality criterion for discourse trees. I provide a first-order formalization of rhetorical structure trees and, on its basis, I derive an algorithm that constructs all the valid rhetorical trees that can be associated with a given discourse.

Marcu, D. [Univ. of Toronto, Ontario (Canada)

1996-12-31

282

Assignment: Minimum Spanning Trees Name: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  

E-print Network

Algorithms Assignment: Minimum Spanning Trees Name 0 11 1 0 00 1 11 0 00 1 11 0011 (a) Find a spanning tree for the Petersen graph with minimum height is at most 2. 2 #12;2. Minimum and maximum spanning trees for the weighted Petersen graph. I J E 4 3 H B C D

Bar-Noy, Amotz

283

The Tree Worker's Manual. [Revised.  

ERIC Educational Resources Information Center

This manual acquaints readers with the general operations of the tree care industry. The manual covers subjects important to a tree worker and serves as a training aid for workers at the entry level as tree care professionals. Each chapter begins with a set of objectives and may include figures, tables, and photographs. Ten chapters are included:…

Lilly, S. J.

284

Singular spectrum for radial trees  

E-print Network

We prove several results showing that absolutely continuous spectrum for the Laplacian on radial trees is a rare event. In particular, we show that metric trees with unbounded edges have purely singular spectrum and that generically (in the sense of Baire) radial trees have purely singular continuous spectrum.

Jonathan Breuer; Rupert L. Frank

2008-06-03

285

Trees and Dags An Introduction  

E-print Network

Chapter 5 Trees and Dags An Introduction to Separation Logic c #2007 John C. Reynolds February 28, 2007 In this chapter, we consider various representations of abstract tree­like data. In general­expressions are the initial lawless algebra with an infinite number of constants and one binary operation.) 5.1 Trees We use

Andrews, Peter B.

286

Our Air: Unfit for Trees.  

ERIC Educational Resources Information Center

To help urban, suburban, and rural tree owners know about air pollution's effects on trees and their tolerance and intolerance to pollutants, the USDA Forest Service has prepared this booklet. It answers the following questions about atmospheric pollution: Where does it come from? What can it do to trees? and What can we do about it? In addition,…

Dochinger, Leon S.

287

Building Your Own Abseil Tree.  

ERIC Educational Resources Information Center

The foot and mouth crisis forced many British outdoor education providers to develop new options. The construction of an abseiling tree is described, which requires a living, healthy, straight tree with a trunk thick enough to remain stable under load and with few branches in the lower 15-20 meters. An abseil tree code of practice is presented.…

Barnett, Des

2002-01-01

288

Random Trees, Heights, and Large Deviations  

Microsoft Academic Search

We present here a general framework to devise a law of large numbers for the height of random trees. Our model unifies the treatment of many examples of the literature such as binary search trees, median-of-(2k + 1) trees, random recursive trees, plane oriented trees, digital search trees, scale-free trees, and all polynomial families of increasing trees, among others. The

Nicolas Broutin

289

Introduction Finite-State Tree Automata  

E-print Network

Introduction Finite-State Tree Automata The Complementation Problem for Automata on Innite Trees;Introduction Finite-State Tree Automata The Complementation Problem for Automata on Innite Trees Outline 1 Introduction Motivation Basic Denitions 2 Finite-State Tree Automata Denitions Muller Tree Automaton Parity

Rabinovich, Alexander

290

Riparian Forest Grows Trees fall in  

E-print Network

Riparian Forest Grows Trees Die Trees fall in the lake Trees leave the littoral zone "Life" Cycle of Coarse Woody Habitat #12;Riparian Forest Grows What factors drive the species composition and stand structure? Trees Die Trees fall in the lake Trees leave the littoral zone #12;Riparian Forest Grows What

291

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. PMID:23167951

2012-01-01

292

Rate of tree carbon accumulation increases continuously with tree size.  

PubMed

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence. PMID:24429523

Stephenson, N L; Das, A J; Condit, R; Russo, S E; Baker, P J; Beckman, N G; Coomes, D A; Lines, E R; Morris, W K; Rüger, N; Alvarez, E; Blundo, C; Bunyavejchewin, S; Chuyong, G; Davies, S J; Duque, A; Ewango, C N; Flores, O; Franklin, J F; Grau, H R; Hao, Z; Harmon, M E; Hubbell, S P; Kenfack, D; Lin, Y; Makana, J-R; Malizia, A; Malizia, L R; Pabst, R J; Pongpattananurak, N; Su, S-H; Sun, I-F; Tan, S; Thomas, D; van Mantgem, P J; Wang, X; Wiser, S K; Zavala, M A

2014-03-01

293

Rate of tree carbon accumulation increases continuously with tree size  

NASA Astrophysics Data System (ADS)

Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

Stephenson, N. L.; Das, A. J.; Condit, R.; Russo, S. E.; Baker, P. J.; Beckman, N. G.; Coomes, D. A.; Lines, E. R.; Morris, W. K.; Rüger, N.; Álvarez, E.; Blundo, C.; Bunyavejchewin, S.; Chuyong, G.; Davies, S. J.; Duque, Á.; Ewango, C. N.; Flores, O.; Franklin, J. F.; Grau, H. R.; Hao, Z.; Harmon, M. E.; Hubbell, S. P.; Kenfack, D.; Lin, Y.; Makana, J.-R.; Malizia, A.; Malizia, L. R.; Pabst, R. J.; Pongpattananurak, N.; Su, S.-H.; Sun, I.-F.; Tan, S.; Thomas, D.; van Mantgem, P. J.; Wang, X.; Wiser, S. K.; Zavala, M. A.

2014-03-01

294

From Gene to Organismal Phylogeny: Reconciled Trees and the Gene Tree/Species Tree Problem  

E-print Network

From Gene to Organismal Phylogeny: Reconciled Trees and the Gene Tree/Species Tree Problem Roderic The processes of gene duplication, loss, and lineage sorting can result in incongruence between the phylog- enies of genes and those of species. This incongruence complicates the task of inferring the latter from

Page, Roderic

295

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

296

RESOVING THE GENE TREE AND SPECIES TREE PROBLEM BY PHYLOGENETIC MINING  

E-print Network

RESOVING THE GENE TREE AND SPECIES TREE PROBLEM BY PHYLOGENETIC MINING XIAOXU HAN Department and species tree problem remains a central problem in phylogenomics. To overcome this problem, gene.1. Gene tree and species tree problem The gene tree/species tree problem is still an important problem

Wong, Limsoon

297

Spanning Trees A spanning tree of a simple graph G is a sub-  

E-print Network

return T Minimum Spanning Trees A minimum spanning tree of a weighted simple graph G is a spanning tree1 Spanning Trees A spanning tree of a simple graph G is a sub- graph that is a tree and contains every vertex. A simple graph is connected if and only if it has a spanning tree. Depth-first search

Bylander, Tom

298

Exact solutions for species tree inference from discordant gene trees.  

PubMed

Phylogenetic analysis has to overcome the grant challenge of inferring accurate species trees from evolutionary histories of gene families (gene trees) that are discordant with the species tree along whose branches they have evolved. Two well studied approaches to cope with this challenge are to solve either biologically informed gene tree parsimony (GTP) problems under gene duplication, gene loss, and deep coalescence, or the classic RF supertree problem that does not rely on any biological model. Despite the potential of these problems to infer credible species trees, they are NP-hard. Therefore, these problems are addressed by heuristics that typically lack any provable accuracy and precision. We describe fast dynamic programming algorithms that solve the GTP problems and the RF supertree problem exactly, and demonstrate that our algorithms can solve instances with data sets consisting of as many as 22 taxa. Extensions of our algorithms can also report the number of all optimal species trees, as well as the trees themselves. To better asses the quality of the resulting species trees that best fit the given gene trees, we also compute the worst case species trees, their numbers, and optimization score for each of the computational problems. Finally, we demonstrate the performance of our exact algorithms using empirical and simulated data sets, and analyze the quality of heuristic solutions for the studied problems by contrasting them with our exact solutions. PMID:24131054

Chang, Wen-Chieh; Górecki, Pawe?; Eulenstein, Oliver

2013-10-01

299

Structural regression trees  

SciTech Connect

In many real-world domains the task of machine learning algorithms is to learn a theory for predicting numerical values. In particular several standard test domains used in Inductive Logic Programming (ILP) are concerned with predicting numerical values from examples and relational and mostly non-determinate background knowledge. However, so far no ILP algorithm except one can predict numbers and cope with nondeterminate background knowledge. (The only exception is a covering algorithm called FORS.) In this paper we present Structural Regression Trees (SRT), a new algorithm which can be applied to the above class of problems. SRT integrates the statistical method of regression trees into ILP. It constructs a tree containing a literal (an atomic formula or its negation) or a conjunction of literals in each node, and assigns a numerical value to each leaf. SRT provides more comprehensible results than purely statistical methods, and can be applied to a class of problems most other ILP systems cannot handle. Experiments in several real-world domains demonstrate that the approach is competitive with existing methods, indicating that the advantages are not at the expense of predictive accuracy.

Kramer, S. [Austrian Research Inst. for Artificial Intelligence, Vienna (Austria)

1996-12-31

300

2-4 Trees and B-Trees To know what a 2-4 tree is (9.1).  

E-print Network

809 CHAPTER 9 2-4 Trees and B-Trees Objectives · To know what a 2-4 tree is (§9.1). · To design the Tree24 class that implements the Tree interface (§9.2). · To search an element in a 2-4 tree (§9.3). · To insert an element in a 2-4 tree and know how to split a node (§9.4). · To delete an element from a 2

Liang, Y. Daniel

301

Laccase versus Laccase-Like Multi-Copper Oxidase: A Comparative Study of Similar Enzymes with Diverse Substrate Spectra  

PubMed Central

Laccases (EC 1.10.3.2) are multi-copper oxidases that catalyse the one-electron oxidation of a broad range of compounds including substituted phenols, arylamines and aromatic thiols to the corresponding radicals. Owing to their broad substrate range, copper-containing laccases are versatile biocatalysts, capable of oxidizing numerous natural and non-natural industry-relevant compounds, with water as the sole by-product. In the present study, 10 of the 11 multi-copper oxidases, hitherto considered to be laccases, from fungi, plant and bacterial origin were compared. A substrate screen of 91 natural and non-natural compounds was recorded and revealed a fairly broad but distinctive substrate spectrum amongst the enzymes. Even though the enzymes share conserved active site residues we found that the substrate ranges of the individual enzymes varied considerably. The EC classification is based on the type of chemical reaction performed and the actual name of the enzyme often refers to the physiological substrate. However, for the enzymes studied in this work such classification is not feasible, even more so as their prime substrates or natural functions are mainly unknown. The classification of multi-copper oxidases assigned as laccases remains a challenge. For the sake of simplicity we propose to introduce the term “laccase-like multi-copper oxidase” (LMCO) in addition to the term laccase that we use exclusively for the enzyme originally identified from the sap of the lacquer tree Rhus vernicifera. PMID:23755261

Reiss, Renate; Ihssen, Julian; Richter, Michael; Eichhorn, Eric; Schilling, Boris; Thöny-Meyer, Linda

2013-01-01

302

Laccase versus laccase-like multi-copper oxidase: a comparative study of similar enzymes with diverse substrate spectra.  

PubMed

Laccases (EC 1.10.3.2) are multi-copper oxidases that catalyse the one-electron oxidation of a broad range of compounds including substituted phenols, arylamines and aromatic thiols to the corresponding radicals. Owing to their broad substrate range, copper-containing laccases are versatile biocatalysts, capable of oxidizing numerous natural and non-natural industry-relevant compounds, with water as the sole by-product. In the present study, 10 of the 11 multi-copper oxidases, hitherto considered to be laccases, from fungi, plant and bacterial origin were compared. A substrate screen of 91 natural and non-natural compounds was recorded and revealed a fairly broad but distinctive substrate spectrum amongst the enzymes. Even though the enzymes share conserved active site residues we found that the substrate ranges of the individual enzymes varied considerably. The EC classification is based on the type of chemical reaction performed and the actual name of the enzyme often refers to the physiological substrate. However, for the enzymes studied in this work such classification is not feasible, even more so as their prime substrates or natural functions are mainly unknown. The classification of multi-copper oxidases assigned as laccases remains a challenge. For the sake of simplicity we propose to introduce the term "laccase-like multi-copper oxidase" (LMCO) in addition to the term laccase that we use exclusively for the enzyme originally identified from the sap of the lacquer tree Rhus vernicifera. PMID:23755261

Reiss, Renate; Ihssen, Julian; Richter, Michael; Eichhorn, Eric; Schilling, Boris; Thöny-Meyer, Linda

2013-01-01

303

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.

304

The fault-tree compiler  

NASA Technical Reports Server (NTRS)

The Fault Tree Compiler Program is a new reliability tool used to predict the top event probability for a fault tree. Five different gate types are allowed in the fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N gates. The high level input language is easy to understand and use when describing the system tree. In addition, the use of the hierarchical fault tree capability can simplify the tree description and decrease program execution time. The current solution technique provides an answer precise (within the limits of double precision floating point arithmetic) to the five digits in the answer. The user may vary one failure rate or failure probability over a range of values and plot the results for sensitivity analyses. The solution technique is implemented in FORTRAN; the remaining program code is implemented in Pascal. The program is written to run on a Digital Corporation VAX with the VMS operation system.

Martensen, Anna L.; Butler, Ricky W.

1987-01-01

305

Tree Level Gauge Mediation  

E-print Network

We propose a new scheme in which supersymmetry breaking is communicated to the MSSM sfermions by GUT gauge interactions at the tree level. The (positive) contribution of MSSM fields to $\\text{Str}(\\mathcal{M}^2)$ is automatically compensated by a (negative) contribution from heavy fields. Sfermion masses are flavour universal, thus solving the supersymmetric flavour problem. In the simplest SO(10) embedding, the ratio of different sfermion masses is predicted and differs from mSugra and other schemes, thus making this framework testable at the LHC. Gaugino masses are generated at the loop level but enhanced by model dependent factors.

Marco Nardecchia; Andrea Romanino; Robert Ziegler

2009-11-27

306

Ice Roads: Steiner Trees  

NSDL National Science Digital Library

In this outdoor activity, learners use pegs (like tent pegs) and string or elastic to simulate drill sites and roads in Northern Canada. Learners are challenged with figuring out how to connect the roads to all the drill sites while keeping the total road length to a minimum. They'll discover that intersections or "Steiner" points provide efficiency between points within a network. Use this activity to introduce learners to computer science themes including Steiner trees, algorithms, and NP-complete problems. Variations, extensions, background information, and solutions are included in the PDF.

Tim Bell

1998-01-01

307

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.

308

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 Noble

309

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

310

Cellular automata on Cayley tree  

E-print Network

In this paper, we study cellular automata on Cayley tree of order 2 over the field $\\mathbb Z_p$ (the set of prime numbers modulo $p$). We construct the rule matrix corresponding to finite cellular automata on Cayley tree. Further, we analyze the reversibility problem of this cellular automata for some given values of $a,b,c,d\\in \\mathbb{Z}_{p}\\setminus {0}$ and the levels $n$ of Cayley tree. We compute the measure-theoretical entropy of the cellular automata which we define on Cayley tree.

Hasan Akin

2012-11-30

311

Tree Modeling and Dynamics Simulation  

NASA Astrophysics Data System (ADS)

This paper introduces the theory about tree modeling and dynamic movements simulation in computer graphics. By comparing many methods we choose Geometry-based rendering as our method. The tree is decomposed into branches and leaves, under the rotation and quaternion methods we realize the tree animation and avoid the Gimbals Lock in Euler rotation. We take Orge 3D as render engine, which has good graphics programming ability. By the end we realize the tree modeling and dynamic movements simulation, achieve realistic visual quality with little computation cost.

Tian-shuang, Fu; Yi-bing, Li; Dong-xu, Shen

312

Equation Node a_down[ext,tree  

E-print Network

Equation Node exchange7 #12; Unary Binary tree 0 a_down[ext,tree] a_down[inp,tree] a_down_succ[left,out,ext] id_succ[right,inp,ext] id_succ[right,out,ext] r_down[ext,tree] r_down[inp,tree] r_down[out,tree] 1 a_down[ext,tree]=1/2 a_down[inp,tree]=1/2 a_down[out,tree]=1/2 exch_left_succ[inp,ext]=1/2 exch_left_succ[inp,out]=1

Jeannet, Bertrand

313

Lecture 10: Minimum Spanning Trees and Prim's Algorithm  

E-print Network

Lecture 10: Minimum Spanning Trees and Prim's Algorithm CLRS Chapter 23 Outline of this Lecture . Spanning trees and minimum spanning trees. . The minimum spanning tree (MST) problem. . Prim's algorithm Tree 2, w=71 Tree 3, w=72 Tree 1. w=74 Minimum spanning tree 4 #12; Minimum Spanning Trees A Minimum

Golin, Mordecai J.

314

Lecture 7: Minimum Spanning Trees and Prim's Algorithm  

E-print Network

Lecture 7: Minimum Spanning Trees and Prim's Algorithm CLRS Chapter 23 Outline of this Lecture Spanning trees and minimum spanning trees. The minimum spanning tree (MST) problem. The generic Tree 2, w=71 Tree 3, w=72 Tree 1. w=74 Minimum spanning tree 4 #12;Minimum Spanning Trees A Minimum

Wu, Dekai

315

Lecture 7: Minimum Spanning Trees and Prim's Algorithm  

E-print Network

Lecture 7: Minimum Spanning Trees and Prim's Algorithm CLRS Chapter 23 Outline of this Lecture ffl Spanning trees and minimum spanning trees. ffl The minimum spanning tree (MST) problem. ffl The generic graph Tree 2, w=71 Tree 3, w=72 Tree 1. w=74 Minimum spanning tree 4 #12; Minimum Spanning Trees

Wu, Dekai

316

Minimum Spanning Trees Suggested Reading: Chapter 23.  

E-print Network

Minimum Spanning Trees CSE 680 Suggested Reading: Chapter 23. 1 Greedy Method Optimization Problem best at this moment 1 #12;2 Minimum Spanning Trees · Spanning tree: A spanning tree of a connected = (V, E), find a span- ning tree of minimum cost. · Assume V = {1, 2, . . . , n}. 2 #12;3 Prim

Lai, Ten-Hwang "Steve"

317

Minimum Spanning Trees Suggested Reading: Chapter 23.  

E-print Network

Minimum Spanning Trees CSE 2331 Suggested Reading: Chapter 23. 1 Greedy Method Optimization Problem best at this moment 1 #12;2 Minimum Spanning Trees · Spanning tree: A spanning tree of a connected = (V, E), find a span- ning tree of minimum cost. · Assume V = {1, 2, . . . , n}. 2 #12;3 Prim

Lai, Ten-Hwang "Steve"

318

COMPONENT User's Guide Maps between trees  

E-print Network

COMPONENT User's Guide Chapter 7 Maps between trees This chapter describes tree mapping routines in COMPONENT. These routines allow you to map gene trees onto species trees, parasite phylogenies onto host phylogenies, and taxon cladograms onto area cladograms. Overview This section introduces some basics of tree

Page, Roderic

319

Operations on Images Using Quad Trees  

Microsoft Academic Search

A quad tree for representing a picture is a tree in which successively deeper levels represent successively finer subdivisions of picture area. An algorithm is given for superposing N quad trees in time proportional to the total number of nodes in the trees. Warnock-type algorithms are then presented for building the quad tree for the picture of the boundary of

Gregory M. Hunter; Kenneth Steiglitz

1979-01-01

320

Critical RWRE on trees and tree-indexed random walks  

Microsoft Academic Search

We study the behavior of Random Walk in Random Environment (RWRE) on trees in the critical case left open in previous work. Representing the random walk by an electrical network, we assume that the ratios of resistances of neighboring edges of a tree Gamma are i.i.d.random variables whose logarithms have mean zero and finite variance. Then the resulting RWRE is

Robin Pemantle; Yuval Peres

2004-01-01

321

DIF Trees: Using Classification Trees to Detect Differential Item Functioning  

ERIC Educational Resources Information Center

A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

Vaughn, Brandon K.; Wang, Qiu

2010-01-01

322

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

323

Tree-grass and tree-tree interactions in a temperate savanna  

E-print Network

intraspecific competition among even-aged woody plants (Kenkel 1988, Baldwin et al. 2000) and woody saplings (Shainsky and Radosevich 1992) has been demonstrated, evidence for the importance of such interactions in natural woodlands (Duncan 1991...). Evidence of competition between savanna trees has been largely inferential (Penridge and Walker 1986, Kenkel 1988, Martens et al. 1997, Scholes and Archer 1997), but has indicated that competition intensity increases with increasing tree density. Tree...

Simmons, Mark Trevor

2004-11-15

324

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

325

Distributed Merge Trees  

SciTech Connect

Improved simulations and sensors are producing datasets whose increasing complexity exhausts our ability to visualize and comprehend them directly. To cope with this problem, we can detect and extract significant features in the data and use them as the basis for subsequent analysis. Topological methods are valuable in this context because they provide robust and general feature definitions. As the growth of serial computational power has stalled, data analysis is becoming increasingly dependent on massively parallel machines. To satisfy the computational demand created by complex datasets, algorithms need to effectively utilize these computer architectures. The main strength of topological methods, their emphasis on global information, turns into an obstacle during parallelization. We present two approaches to alleviate this problem. We develop a distributed representation of the merge tree that avoids computing the global tree on a single processor and lets us parallelize subsequent queries. To account for the increasing number of cores per processor, we develop a new data structure that lets us take advantage of multiple shared-memory cores to parallelize the work on a single node. Finally, we present experiments that illustrate the strengths of our approach as well as help identify future challenges.

Morozov, Dmitriy; Weber, Gunther

2013-01-08

326

Discordance of Species Trees with Their Most Likely Gene Trees: The Case of Five Taxa  

Microsoft Academic Search

Under a coalescent model for within-species evolution, gene trees may differ from species trees to such an extent that the gene tree topology most likely to evolve along the branches of a species tree can disagree with the species tree topology. Gene tree topologies that are more likely to be produced than the topology that matches that of the species

NOAH A. ROSENBERG; RANDA TAO

2008-01-01

327

iGLASS: An Improvement to the GLASS Method for Estimating Species Trees from Gene Trees  

E-print Network

iGLASS: An Improvement to the GLASS Method for Estimating Species Trees from Gene Trees ETHAN M. JEWETT and NOAH A. ROSENBERG ABSTRACT Several methods have been designed to infer species trees from gene trees while taking into account gene tree/species tree discordance. Although some of these methods

Rosenberg, Noah

328

Non-crossing Trees are Almost Conditioned Galton-Watson trees1  

E-print Network

Non-crossing Trees are Almost Conditioned Galton-Watson trees1 Jean-Fran¸cois Marckert Alois-10, A - 1040 Wien, Austria alois.panholzer@tuwien.ac.at ABSTRACT: A non-crossing tree (NC-tree) is a tree drawn seg- ments that do not cross. In this paper, we show that NC-trees with size n are conditioned Galton

Marckert, Jean-François

329

Fuzzy SLIQ decision tree algorithm.  

PubMed

Traditional decision tree algorithms face the problem of having sharp decision boundaries which are hardly found in any real-life classification problems. A fuzzy supervised learning in Quest (SLIQ) decision tree (FS-DT) algorithm is proposed in this paper. It is aimed at constructing a fuzzy decision boundary instead of a crisp decision boundary. Size of the decision tree constructed is another very important parameter in decision tree algorithms. Large and deeper decision tree results in incomprehensible induction rules. The proposed FS-DT algorithm modifies the SLIQ decision tree algorithm to construct a fuzzy binary decision tree of significantly reduced size. The performance of the FS-DT algorithm is compared with SLIQ using several real-life datasets taken from the UCI Machine Learning Repository. The FS-DT algorithm outperforms its crisp counterpart in terms of classification accuracy. FS-DT also results in more than 70% reduction in size of the decision tree compared to SLIQ. PMID:18784012

Chandra, B; Varghese, P Paul

2008-10-01

330

Genetic conservation of native trees  

E-print Network

Genetic conservation of native trees Scott McG. Wilson1 and C. J. A. Samuel Over recent years, the genetic conservation of British native tree populations has become an increasingly important part policy-makers in the genetic basis of forest biodiversity conservation, both at the UK and, more

331

Hazard Tree Management for Camps.  

ERIC Educational Resources Information Center

The principles behind a camp's hazard tree program are, first, identifying and removing those hazards that offer a clear, immediate threat, and then creating a management plan for the other trees. The plan should be written and contain goals and objectives, field evaluations, and treatments. Follow-up evaluations should be done annually and after…

Kong, Earl

2002-01-01

332

The tree of one percent  

PubMed Central

Two significant evolutionary processes are fundamentally not tree-like in nature - lateral gene transfer among prokaryotes and endosymbiotic gene transfer (from organelles) among eukaryotes. To incorporate such processes into the bigger picture of early evolution, biologists need to depart from the preconceived notion that all genomes are related by a single bifurcating tree. PMID:17081279

Dagan, Tal; Martin, William

2006-01-01

333

4-H SEEDLING TREE PROGRAM  

E-print Network

for refor- estation, erosion control, wind and sound barriers, wild- life habitats, and other conservation2014 4-H SEEDLING TREE PROGRAM Seedling trees for conservation planting in the spring of 2014 Forest Service, are available to anyone, but must be used for conservation purposes. They may be planted

Stephens, Graeme L.

334

Computing minimum spanning trees efficiently  

Microsoft Academic Search

A ubiquitous problem in mathematical programming is the calculation of minimum spanning trees. Minimum spanning tree algorithms find application in such diverse areas as: least cost electrical wiring, minimum cost connecting communication and transportation networks, network reliability problems, minimum stress networks, clustering and numerical taxonomy, algorithms for solving traveling salesman problems, and multiterminal network flows. It is therefore important to

A. Kershenbaum; R. Van Slyke

1972-01-01

335

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).

E. Strauss

336

Carbon14 in tree rings  

Microsoft Academic Search

In order to investigate how reliably the carbon 14 content of tree rings reflects that of atmospheric carbon dioxide, two types of determinations were carried out: (1) carbon 14 determinations in annual rings from the beginning of this century until 1974 and (2) carbon 14 determinations in synchronous wood from the North American bristlecone pine and from European oak trees,

William F. Cain; Hans E. Suess

1976-01-01

337

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

338

Ancient stunted trees on cliffs  

Microsoft Academic Search

An undisturbed ancient woodland, dominated by tiny, slow-growing and widely spaced trees, grows on vertical cliffs of the Niagara escarpment in southern Canada. To investigate whether this woodland is unusual or is part of a previously undetected global pattern, we sampled ages and radial growth rates for trees on cliffs in the United States and in western Europe. We find

D. W. Larson; U. Matthes; J. A. Gerrath; J. M. Gerrath; J. C. Nekola; G. L. Walker; S. Porembski; A. Charlton; N. W. K. Larson

1999-01-01

339

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

340

On Cartesian trees and range minimum queries  

E-print Network

We present new results on Cartesian trees with applications in range minimum queries and bottleneck edge queries. We introduce a cache-oblivious Cartesian tree for solving the range minimum query problem, a Cartesian tree ...

Demaine, Erik D.

341

7 CFR 1214.3 - Christmas tree.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture...DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information...

2014-01-01

342

7 CFR 1214.3 - Christmas tree.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture...DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information...

2012-01-01

343

7 CFR 1214.3 - Christmas tree.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Christmas tree. 1214.3 Section 1214.3 Agriculture...DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information...

2013-01-01

344

75 FR 25103 - Tree Assistance Program  

Federal Register 2010, 2011, 2012, 2013, 2014

...Corporation 7 CFR Part 1416 RIN 0560-AH96 Tree Assistance Program AGENCY: Farm Service...implements specific requirements for the Tree Assistance Program (TAP) authorized by...assistance to eligible orchardists and nursery tree growers to replant or rehabilitate...

2010-05-07

345

In Search of Moon Trees  

NSDL National Science Digital Library

In 1971, hundreds of tree seedlings germinated aboard NASA's Apollo 14 mission to the moon. A few years later, they were planted around the nation, often with much fanfare. However, no one kept a systematic record of these plantings, and as a result, the whereabouts of most of the trees remains a mystery. Visitors can read or listen to an account of the history and current status of them at this Web site, and follow links to access additional information relating to the story or to learn the location of known Moon trees. NASA scientist Dave Williams continues to search for the remaining trees and encourages readers to contact him if they believe they know of trees not currently mentioned on his list. What this site lacks in colorful, interactive features is more than made up for by its engaging feature story.

Phillips, Tony.

2002-01-01

346

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

347

Tree reconstruction from partial orders  

SciTech Connect

The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n[sup 3]) time and from POM experiments in O(n[sup 4]) time.

Kannan, S.K. (Arizona Univ., Tucson, AZ (United States)); Warnow, T.J. (Sandia National Labs., Albuquerque, NM (United States))

1993-01-01

348

Tree reconstruction from partial orders  

SciTech Connect

The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n{sup 3}) time and from POM experiments in O(n{sup 4}) time.

Kannan, S.K. [Arizona Univ., Tucson, AZ (United States); Warnow, T.J. [Sandia National Labs., Albuquerque, NM (United States)

1993-03-01

349

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. PMID:21949369

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

2011-01-01

350

Genetically optimized fuzzy decision trees.  

PubMed

In this study, we are concerned with genetically optimized fuzzy decision trees (G-DTs). Decision trees are fundamental architectures of machine learning, pattern recognition, and system modeling. Starting with the generic decision tree with discrete or interval-valued attributes, we develop its fuzzy set-based generalization. In this generalized structure we admit the values of the attributes that are represented by some membership functions. Such fuzzy decision trees are constructed in the setting of genetic optimization. The underlying genetic algorithm optimizes the parameters of the fuzzy sets associated with the individual nodes where they play a role of fuzzy "switches" by distributing a flow of processing completed within the tree. We discuss various forms of the fitness function that help capture the essence of the problem at hand (that could be either of classification nature when dealing with discrete outputs or regression-like when handling a continuous output variable). We quantify a nature of the generalization of the tree by studying an optimally adjusted spreads of the membership functions located at the nodes of the decision tree. A series of experiments exploiting synthetic and machine learning data is used to illustrate the performance of the G-DTs. PMID:15971931

Pedrycz, Witold; Sosnowski, Zenon A

2005-06-01

351

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. PMID:20445090

Arsuaga, Juan Luis

2010-01-01

352

How Monkeys Use Energy to Leap from Tree to Tree  

NSDL National Science Digital Library

The representation is a diagram with accompanying text, showing conversions as energy goes from the sun (electromagnetic) to the tree (chemical) to the monkey; describes how the monkey converts chemical energy into motion and heat.

David E Watson

353

Tree Search and Quantum Computation  

E-print Network

Traditional tree search algorithms supply a blueprint for modeling problem solving behaviour. A diverse spectrum of problems can be formulated in terms of tree search. Quantum computation, in particular Grover's algorithm, has aroused a great deal of interest since it allows for a quadratic speedup to be obtained in search procedures. In this work we consider the impact of incorporating classical search concepts alongside Grover's algorithm into a hybrid quantum search system. Some of the crucial points examined include: (1) the reverberations of contemplating the use of non-constant branching factors; (2) determining the consequences of incorporating an heuristic perspective into a quantum tree search model.

Luís Tarrataca; Andreas Wichert

2015-02-06

354

On Steiner trees and minimum spanning trees in hypergraphs  

Microsoft Academic Search

The bottleneck of the state-of-the-art algorithms for geometric Steiner problems is usually the concatenation phase, where the prevailing approach treats the generated full Steiner trees as edges of a hypergraph and uses an LP-relaxation of the minimum spanning tree in hypergraph (MSTH) problem. We study this original and some new equivalent relaxations of this problem and clarify their relations to

Tobias Polzin; Siavash Vahdati Daneshmand

2003-01-01

355

S-Tree: a technique for buffered routing tree synthesis  

Microsoft Academic Search

We present the S-Tree algorithm for synthesis of buffered interconnects. The approach incorporates a unique combination of real-world issues (handling of routing and buffer blockages, cost minimization, critical sink isolation, sink polarities), robustness and scalability. The algorithm is able to achieve the slack comparable to that of buffered P-Tree [7] using less resources (wire and buffers) in an order of

Miloš Hrki?; John Lillis

2002-01-01

356

On some relations between 2-trees and tree metrics  

Microsoft Academic Search

A tree function (TF) t on a finite set X is a real function on the set of the pairs of elements of X satisfying the four-point condition: for all distinctx, y, z, w ? X, t(xy)+t(zw)? max{t(xz) + t(yw), t(xw) + t(yz)}. Equivalently, t is representable by the lengths of the paths between the leaves of a valued tree

Bruno Leclerc; Vladimir Makarenkov

1998-01-01

357

Vascularization with trees that alternate with upside-down trees  

NASA Astrophysics Data System (ADS)

This article describes the generation of dendritic flow architectures that provide maximum side-to-side flow access, across a vascularized body. The flow architecture consists of trees that alternate with upside-down trees (a ,b,a,b,…). If in tree "a" the flow is from root to canopy, in tree "b" the flow is from canopy to root. This means that the flow proceeds in the same direction through all the trees, i.e., the flow is oriented side-to-side, or line-to-line. The channel cross sections are rectangular, and they all have the same depth. The article shows under what conditions the tree vascularization offers greater flow access than parallel single-scale channels oriented perpendicularly to the two parallel lines. The analytical part of the work is based on the assumption of fully developed laminar flow in every channel. The numerical part consists of simulations of three-dimensional laminar flow through the entire tree architecture and its many bifurcations. It is shown that tree vascularization is more attractive than parallel channels when the number of bifurcation levels increases, the global porosity of the vascularized body decreases, and the global svelteness (Sv) of the flow architecture increases. The nonuniformity (maldistribution) of flow rates through ramifications of the same rank becomes nonnegligible when the pressure drop number (Be) exceeds 109. The optimal step in the sizes of cross-sectional areas from one channel to the channel of the next rank is closely approximated by 22/3 even when the cross section is not square or round. The agreement between analysis and numerical simulation and optimization is good.

Zhang, Houlei; Lorente, Sylvie; Bejan, Adrian

2007-05-01

358

AVL Tree Applet  

NSDL National Science Digital Library

On its first applet interface, this visualization shows randomly generated input and then allows user to add user defined input. In addition, it has tree size control options; sound options that work seamlessly with all the animations; the animation speed control options. Textual description of each operation as well as pre and post-order traversals are provided in the visualization. Other fancy options like shape control feature and direction control features are also included. Moreover, images on command buttons help users use this tool intuitively. The visualization also shows the basic splay operation for comparison to AVL. This visualization provides several options like user defined data, step-wise speed control, description of each operation with valuable visual effects so that a user can fit the tool to his/her preference. It also provides sound effects and animation effect, in particular, rotation signs before executing operations. This application is highly intuitive with simple and smooth animation. The descriptions after the operation has completed give an insight into what operations the Algorithm visualization went through. The write up provided by author for the algorithm in general is also insightful. Interface provides options to insert node, delete node and find nodes in predetermined or user defined dataset. It also provides good control over the speed of animation. Despite its neat design, the visualization is missing some options. The next button is missing (hence no step by step trace capability) which could have been an added advantage. The layout is pretty decent but it cannot support a large set of numbers. It shows the basic splay operation which was missing in earlier visualizations. But sadly, one cannot control the pacing of the splay operation and it splays the node selected to the root through a series of fast visual iterations. One needs to control the pace of these iterations to have better understanding of the AVL concept which forms the basis of AVL. Further, once we press 'AVL' button, there is no getting back. One has to have a basic knowledge of the BSTs and Self Balancing trees to work with this visualization and this cannot be given to novices who have not taken any Data Structures course till now. Though a beef-up of the basic operations by providing pace control, 'Previous' and 'Next' Buttons, and a short text box that explains what happened in a particular iteration would make this AV a very potent and useful tool for all user groups. Recommended as lecture aide, standalone, self-study suppliment to tutorial or lecture.

Arsen Gogeshvili

359

Implementing Municipal Tree Planting: Los Angeles Million-Tree Initiative  

NASA Astrophysics Data System (ADS)

Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic—living—infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were primarily qualitative, involving interviews, attending meetings and conducting literature reviews. Results indicate that multiple nonprofit and city agency programs are involved in planting and maintaining trees and this has required coordination among groups that here-to-fore were unaccustomed to having to collaborate. The main finding that emerge from this research is that the implementation of such a program in Los Angeles is more complicated than it may seem due to several interacting factors: the need to rely on multiple public and private organizations to put trees into the ground and to maintain them; coordination of these multiple efforts must be centralized, but requires a great deal of time and effort and maybe resisted by some of the partners; funding for planting and long term maintenance must be pieced together from multiple sources; acceptance of trees by residents varies by neighborhood as does tree canopy cover; appropriate nursery supply can be limited; the location of the program within the city administration is determined by who initiates the program.

Pincetl, Stephanie

2010-02-01

360

Implementing municipal tree planting: Los Angeles million-tree initiative.  

PubMed

Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic-living-infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were primarily qualitative, involving interviews, attending meetings and conducting literature reviews. Results indicate that multiple nonprofit and city agency programs are involved in planting and maintaining trees and this has required coordination among groups that here-to-fore were unaccustomed to having to collaborate. The main finding that emerge from this research is that the implementation of such a program in Los Angeles is more complicated than it may seem due to several interacting factors: the need to rely on multiple public and private organizations to put trees into the ground and to maintain them; coordination of these multiple efforts must be centralized, but requires a great deal of time and effort and maybe resisted by some of the partners; funding for planting and long term maintenance must be pieced together from multiple sources; acceptance of trees by residents varies by neighborhood as does tree canopy cover; appropriate nursery supply can be limited; the location of the program within the city administration is determined by who initiates the program. PMID:20016982

Pincetl, Stephanie

2010-02-01

361

Performance Evaluation of Main-Memory R-tree Variants  

Microsoft Academic Search

There have been several techniques proposed for improving the per- formance of main-memory spatial indexes, but there has not been a comparative study of their performance. In this paper we compare the performance of six main-memory R-tree variants: R-tree, R*-tree, Hilbert R-tree, CR-tree, CR*- tree, and Hilbert CR-tree. CR*-trees and Hilbert CR-trees are respectively a natural extension of R*-trees and

Sangyong Hwang; Keunjoo Kwon; Sang Kyun Cha; Byung Suk Lee

2003-01-01

362

Random ancestor trees  

NASA Astrophysics Data System (ADS)

We investigate a network growth model in which the genealogy controls the evolution. In this model, a new node selects a random target node and links either to this target node, or to its parent, or to its grandparent, etc; all nodes from the target node to its most ancient ancestor are equiprobable destinations. The emerging random ancestor tree is very shallow: the fraction gn of nodes at distance n from the root decreases super-exponentially with n, gn = e - 1/(n - 1)!. We find that a macroscopic hub at the root coexists with highly connected nodes at higher generations. The maximal degree of a node at the nth generation grows algebraically as N1/?n, where N is the system size. We obtain the series of nontrivial exponents which are roots of transcendental equations: \\beta_1\\cong 1.351\\,746 , \\beta_2\\cong 1.682\\,201 , etc. As a consequence, the fraction pk of nodes with degree k has an algebraic tail, pk ~ k - ?, with ? = ?1 + 1 = 2.351 746.

Ben-Naim, E.; Krapivsky, P. L.

2010-06-01

363

Trees, networks, and hydrology  

NASA Astrophysics Data System (ADS)

This paper reviews theoretical and observational material on form and function of natural networks appeared in somewhat disparate contexts from physics to biology, whose study is related to hydrologic research. Moving from the exact result that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, we discuss the properties and the dynamic origin of the scale-invariant structure of river patterns and its relation to optimal selection. We argue 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. We thus conclude that one recurrent self-organized mechanism for the dynamic origin of fractal forms is the robust strive for imperfect optimality that we see embedded in many natural patterns, chief and foremost hydrologic ones.

Rinaldo, Andrea; Banavar, Jayanth R.; Maritan, Amos

2006-06-01

364

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

365

Case Study: Visualizing Sets of Evolutionary Trees  

E-print Network

(e.g. the evolutionary tree for frogs) are far from clear. The most common methods for constructing that best explains the data, generally by "walking" from tree to tree. Whatever optimality criterion is used from each other, the consensus tree of the whole set will contain very few internal nodes, all of high

Amenta, Nina

366

Progress in the biotechnology of trees  

Microsoft Academic Search

An increasing world population and rise in demand for tree products, especially wood, has increased the need to produce more timber through planting more forest with improved quality stock. Superior trees are likely to arise from several sources. Firstly, forest trees can be selected from wild populations and cloned using macropropagation techniques already being investigated for fruit tree rootstocks. Alternatively,

N. Hammatt

1992-01-01

367

Tree Induction for Probability-Based Ranking  

Microsoft Academic Search

Tree induction is one of the most effective and widely used methods for building classification models. However, many applications require cases to be ranked by the probability of class membership. Probability estimation trees (PETs) have the same attractive features as classification trees (e.g., comprehensibility, accuracy and efficiency in high dimensions and on large data sets). Unfortunately, decision trees have been

Foster J. Provost; Pedro Domingos

2003-01-01

368

TREE MAINTENANCE AND REMOVAL 31. A GENERAL  

E-print Network

EM 385-1-1 XX Jun 13 SECTION 31 TREE MAINTENANCE AND REMOVAL 31. A GENERAL 31.A.01 References. a, and Distribution; d. ANSI A300 ­ American National Standard for Tree Care Operations ­ Tree, Shrub, and Other Woody- Mounted Elevating and Rotating Aerial Devices. 31.A.02 Tree maintenance or removal shall be performed

US Army Corps of Engineers

369

The Alternating Decision Tree Learning Algorithm  

Microsoft Academic Search

The application of boosting procedures to decisiontree algorithms has been shown to producevery accurate classifiers. These classifiersare in the form of a majority vote overa number of decision trees. Unfortunately,these classifiers are often large, complex anddifficult to interpret. This paper describes anew type of classification rule, the alternatingdecision tree, which is a generalization ofdecision trees, voted decision trees and voteddecision

Yoav Freund; Llew Mason

1999-01-01

370

The Constrained Minimum Spanning Tree (Extended Abstract)  

E-print Network

The Constrained Minimum Spanning Tree Problem (Extended Abstract) R. Ravi* M. X. Goemanst Abstract algorithm, minimum spanning trees, La- grangean relaxation, adjacency relations. 1 Introduction Given. In this case, we can specify a budget L on the total length of the spanning tree and require a tree of minimum

Goemans, Michel X.

371

On the Euclidean Minimum Spanning Tree Problem  

E-print Network

On the Euclidean Minimum Spanning Tree Problem Sanguthevar Rajasekaran Dept. of CSE, University of Connecticut Storrs, CT 06269 Abstract Given a weighted graph G(V, E), a minimum spanning tree for G can a minimum spanning tree for this graph is known as the Euclidean minimum spanning tree problem (EMSTP

Rajasekaran, Sanguthevar

372

"Dangerous" urban trees & community health & safety  

E-print Network

"Dangerous" urban trees & community health & safety Norman Dandy Forest Research #12;Urban trees, safety & climate change · Forest Research project "Climate change and street trees" · Reviews the governance structures relating to [individual] trees in the urban environment · Strong governance protecting

373

Practice Guide Raising trees and shrubs  

E-print Network

Practice Guide Raising trees and shrubs from seed #12;Raising trees and shrubs from seed Peter). Raising trees and shrubs from seed. Forestry Commission Practice Guide. Forestry Commission, Edinburgh. i­iv + 1­28 pp. Keywords: collection; dormancy; germination; pretreatment; processing; storage; tree seeds

374

A Novel Approach for Compressing Phylogenetic Trees  

E-print Network

A Novel Approach for Compressing Phylogenetic Trees Suzanne J. Matthews, Seung-Jin Sul, and Tiffani,sulsj,tlw}@cse.tamu.edu Abstract. Phylogenetic trees are tree structures that depict relation- ships between organisms. Popular analysis techniques often produce large collections of candidate trees, which are expensive to store. We

Williams, Tiffani

375

Action trees and moral judgment Joshua Knobe  

E-print Network

1 Action trees and moral judgment Joshua Knobe Yale University [Forthcoming in Topics in Cognitive of an action tree. A question now arises about the relationship between this action tree representation of the action tree and then go on to use this representation in making moral judgments. The present paper argues

Knobe, Joshua

376

Research Summary Health Benefits of Street Trees  

E-print Network

Research Summary Health Benefits of Street Trees Street trees can have an important role. Health and well-being objectives have been elements of each country's forest strategy, and street trees This research aimed to: o Assess recent economic evidence of the health benefits provided by street trees

377

Growing a Forest for the Trees.  

ERIC Educational Resources Information Center

Describes a tree studies program in a fourth-grade classroom. Students collected local tree seeds and seeds from supermarket fruits, researched growing conditions, and grew seeds under various conditions. Students kept journals on local trees, observing seed dispersal mechanisms and examining rings on trunk slices. Inquiry-based tree studies…

Growing Ideas, 2001

2001-01-01

378

Tree Growth Rings: What They Tell Us.  

ERIC Educational Resources Information Center

Activities in which students can learn to determine the history of a tree from the growth pattern recorded in the rings of a cross-section of a tree are described. Activities include background information, objectives, a list of needed materials per group, and procedures. Cross-sections of four different tree types are included if real tree

Sunal, Dennis W.; Sunal, Cynthia Szymanski

1991-01-01

379

MANAGEMENT INFORMATION SYSTEMS FOR URBAN TREES1  

Microsoft Academic Search

The concept and applications of computerized in- formation systems for the management of urban trees are reviewed. Among their uses are landscape planning, choosing species to be planted, organizing work on trees, departmental planning and evaluation, and public relations. Five types of data required for these purposes pertain to the location of trees, tree characteristics, site characteristics, actions recom- mended,

Henry D. Gerhold; Kim C. Steiner; C. J. Sacksteder

1987-01-01

380

Inferring species trees from gene duplication episodes  

Microsoft Academic Search

Gene tree parsimony, which infers a species tree that implies the fewest gene duplications across a collection of gene trees, is a method for inferring phylogenetic trees from paralogous genes. However, it assumes that all duplications are independent, and therefore, it does not account for large-scale gene duplication events like whole genome duplications. We describe two methods to infer species

J. Gordon Burleigh; Mukul S. Bansal; Oliver Eulenstein; Todd J. Vision

2010-01-01

381

How To Select and Plant a Tree.  

ERIC Educational Resources Information Center

This bulletin furnishes information about selecting and planting trees. The tree selection process includes being aware of the physical characteristics of bare root seedlings, containerized seedlings, balled and burlapped, or potted trees and determining the proper size and root ball proportions. The section on tree planting discusses how to: (1)…

Fazio, James R., Ed.

1991-01-01

382

Urban tree cover: an ecological perspective  

Microsoft Academic Search

Analysis of urban tree cover is generally limited to inventories of tree structure and composition on public lands. This approach provided valuable information for resource management. However, it does not account for all tree cover within an urban landscape, thus providing insufficient information on ecological patterns and processes. We propose evaluating tree cover for an entire urban area that is

Wayne C. Zipperer; Susan M. Sisinni; Richard V. Pouyat; Timothy W. Foresman

1997-01-01

383

Core Based Trees (CBT) Multicast Routing Architecture  

Microsoft Academic Search

CBT is a multicast routing architecture that builds a single delivery tree per group which is shared by all of the group's senders and receivers. Most multicast algorithms build one multicast tree per sender (subnetwork), the tree being rooted at the sender's subnetwork. The primary advantage of the shared tree approach is that it typically offers more favourable scaling characteristics

A. Ballardie

1997-01-01

384

Tunnel of the California Tunnel Tree  

USGS Multimedia Gallery

In this image, the tunnel through the California Tunnel Tree may be seen. The tunnel was cut through the giant sequoia tree in 1895 to allow coaches, and eventually cars, to drive through the tree as part of a marketing stunt. The California Tunnel Tree is the only living giant sequoia with a t...

385

Pigments, Paints, Polymer Coatings, Lacquers, and Printing Inks  

NASA Astrophysics Data System (ADS)

Change is constant in the coatings market. As mergers, acquisitions, and partnerships take shape, consolidation and globalization remain prominent. The 80/20 rule (20% of the firms accounting for 80% of business) takes effect as the need for regulatory and environmental compliance continues to plague the market. In 1975, the United States alone supported about 2000 coatings companies. Today, there are less than half that many.

Ryntz, Rose A.

386

Quantum Simulation of Phylogenetic Trees  

E-print Network

Quantum simulations constructing probability tensors of biological multi-taxa in phylogenetic trees are proposed, in terms of positive trace preserving maps, describing evolving systems of quantum walks with multiple walkers. Basic phylogenetic models applying on trees of various topologies are simulated following appropriate decoherent quantum circuits. Quantum simulations of statistical inference for aligned sequences of biological characters are provided in terms of a quantum pruning map operating on likelihood operator observables, utilizing state-observable duality and measurement theory.

Demosthenes Ellinas; Peter Jarvis

2011-05-09

387

Tree Rings as Temperature Proxies  

Microsoft Academic Search

Tree-ring series provide the most widely distributed and easily accessible archive of annually resolved proxy climate data. In regions with well-defined seasonal growth the annual growth rings of trees provide both chronological control and a continuous time series of proxy environmental variables. The year to year variability of the physical (e.g. width, density) and chemical properties of these annual rings

Brian H. Luckman

2008-01-01

388

Limit theorems for random trees.  

PubMed Central

This paper is concerned with random rooted trees and studies the distribution of the vertices according to their altitude. If the trees are chosen at random with an increasing number of vertices, then, by a suitable normalization, the distribution function of the number of vertices at a given altitude and the distribution function of the total height approach specific limits. Explicit formulas are given for these limit distribution functions and their moments. PMID:11607295

Takàcs, L

1992-01-01

389

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

390

On distances between phylogenetic trees  

Microsoft Academic Search

Different phylogenetic trees for the same group of species are often produced either by proceduresthat use diverse optimality criteria [18] or from different genes [12] in the study of molecularevolution. Comparing these trees to find their similarities (e.g. agreement or consensus) anddissimilarities, i.e. distance, is thus an important issue in computational molecular biology.The nearest neighbor interchange (nni) distance [26, 24,

B. DasGupta; X. He; T. Jiang; M. Li; J. T. Tromp; L. Zhang

1997-01-01

391

Phenological Variation of Forest Trees  

Microsoft Academic Search

\\u000a Observations of Beech trees in Switzerland show relevant differences in the phenology of the single individual. Within the\\u000a collective of Beech trees, the state of phenological development differs from about one to nineteen days for leaf unfolding,\\u000a and about six to thirty-six days for leaf coloring. Data on the occurrence of specific phenophases and their absolute differences\\u000a within a collective

Robert Brügger; Matthias Dobbertin; Norbert Kräuchi

392

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.

393

REPLACEMENT OF TREES UNDER UTILITY WIRES IMPACTS ATTITUDES AND COMMUNITY TREE PROGRAMS  

Microsoft Academic Search

Opinions of people in 54 Pennsylvania munici- palities who received trees through the Municipal Tree Restoration Program (MTRP) were surveyed, and progress in their tree programs also was evaluated. All municipal tree program components, such as ordinances, tree com- missions, inventories, and management plans, were stimulated by the MTRP to varying extents in one or more ways in 91% of

Dana E. Flowers; Henry D. Gerhold

2000-01-01

394

36 CFR 223.4 - Exchange of trees or portions of trees.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests...PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of...

2013-07-01

395

ATV: display and manipulation of annotated phylogenetic trees ATV: display and manipulation of annotated phylogenetic trees  

E-print Network

ATV: display and manipulation of annotated phylogenetic trees 8/10/01 1 ATV: display and manipulation of annotated phylogenetic trees Christian M. Zmasek and Sean R. Eddy Howard Hughes Medical: {zmasek,eddy}@genetics.wustl.edu Key words: tree display, tree viewer, phylogenetic tree, java

Eddy, Sean

396

36 CFR 223.4 - Exchange of trees or portions of trees.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests...PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of...

2012-07-01

397

Revised slightly from Arborist News 14 (2) 24-26, 2005. Tree Biology and Problem Trees  

E-print Network

Revised slightly from Arborist News 14 (2) 24-26, 2005. Tree Biology and Problem Trees By Kevin T. Smith, USDA Forest Service, Durham, NH 03824 USA Modern Arboriculture and Problem Trees: Have you met any problem trees? Have you created any problem trees? Can you spot them early or even prevent them

398

36 CFR 223.4 - Exchange of trees or portions of trees.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests...PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of...

2011-07-01

399

36 CFR 223.4 - Exchange of trees or portions of trees.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests...TIMBER General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions...

2010-07-01

400

36 CFR 223.4 - Exchange of trees or portions of trees.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Exchange of trees or portions of trees. 223.4 Section 223.4 Parks, Forests...PRODUCTS General Provisions § 223.4 Exchange of trees or portions of trees. Trees or portions of...

2014-07-01

401

Improvements to a Class of Distance Matrix Methods for Inferring Species Trees from Gene Trees  

E-print Network

Improvements to a Class of Distance Matrix Methods for Inferring Species Trees from Gene Trees available for inferring species trees from gene trees, the GLASS method of Mossel and Roch (2010 branch length estimates. Further, GLASS and STEAC have been shown to be consistent estimators of tree

Rosenberg, Noah

402

A SIMPLE BIJECTION BETWEEN A SUBCLASS OF 2-BINARY TREES AND TERNARY TREES  

E-print Network

NOTE A SIMPLE BIJECTION BETWEEN A SUBCLASS OF 2-BINARY TREES AND TERNARY TREES HELMUT PRODINGER We consider the subclass of 2-binary trees, where · nodes are labelled black or white, · the root is labelled] that these trees are in bijection with ternary trees (and henceforth enumerated by 1 2n+1 3n n ). In this note we

Wagner, Stephan

403

Multipolar consensus for phylogenetic trees.  

PubMed

Collections of phylogenetic trees are usually summarized using consensus methods. These methods build a single tree, supposed to be representative of the collection. However, in the case of heterogeneous collections of trees, the resulting consensus may be poorly resolved (strict consensus, majority-rule consensus, ...), or may perform arbitrary choices among mutually incompatible clades, or splits (greedy consensus). Here, we propose an alternative method, which we call the multipolar consensus (MPC). Its aim is to display all the splits having a support above a predefined threshold, in a minimum number of consensus trees, or poles. We show that the problem is equivalent to a graph-coloring problem, and propose an implementation of the method. Finally, we apply the MPC to real data sets. Our results indicate that, typically, all the splits down to a weight of 10% can be displayed in no more than 4 trees. In addition, in some cases, biologically relevant secondary signals, which would not have been present in any of the classical consensus trees, are indeed captured by our method, indicating that the MPC provides a convenient exploratory method for phylogenetic analysis. The method was implemented in a package freely available at http://www.lirmm.fr/~cbonnard/MPC.html PMID:17060203

Bonnard, Cécile; Berry, Vincent; Lartillot, Nicolas

2006-10-01

404

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

405

Self-adjusting binary search trees  

Microsoft Academic Search

The splay tree, a self-adjusting form of binary search tree, is developed and analyzed. The binary search tree is a data structure for representing tables and lists so that accessing, inserting, and deleting items is easy. On an n-node splay tree, all the standard search tree operations have an amortized time bound of O(log n) per operation, where by “amortized

Daniel Dominic Sleator; Robert Endre Tarjan

1985-01-01

406

TreeGenes: A Forest Tree Genome Database  

PubMed Central

The Dendrome Project and associated TreeGenes database serve the forest genetics research community through a curated and integrated web-based relational database. The research community is composed of approximately 2 000 members representing over 730 organizations worldwide. The database itself is composed of a wide range of genetic data from many forest trees with focused efforts on commercially important members of the Pinaceae family. The primary data types curated include species, publications, tree and DNA extraction information, genetic maps, molecular markers, ESTs, genotypic, and phenotypic data. There are currently ten main search modules or user access points within this PostgreSQL database. These access points allow users to navigate logically through the related data types. The goals of the Dendrome Project are to (1) provide a comprehensive resource for forest tree genomics data to facilitate gene discovery in related species, (2) develop interfaces that encourage the submission and integration of all genomic data, and to (3) centralize and distribute existing and novel online tools for the research community that both support and ease analysis. Recent developments have focused on increasing data content, functional annotations, data retrieval, and visualization tools. TreeGenes was developed to provide a centralized web resource with analysis and visualization tools to support data storage and exchange. PMID:18725987

Wegrzyn, Jill L.; Lee, Jennifer M.; Tearse, Brandon R.; Neale, David B.

2008-01-01

407

Methane Emissions from Upland Trees  

NASA Astrophysics Data System (ADS)

Most work on methane (CH4) emissions from natural ecosystems has focused on wetlands and wetland soils because they are predictable emitters and relatively simple to quantify. Less attention has been directed toward upland ecosystems that cover far larger areas, but are assumed to be too dry to emit CH4. There is abundant evidence that upland ecosystems emit small amounts of CH4 during hot moments that collectively constitute a significant source in the global budget of this potent greenhouse gas. We have established two transects across natural moisture gradients in two forests near Annapolis, Maryland. Both tree and soil methane fluxes were measured using chamber methods. Each tree chamber was custom fit to the stem near the base. In addition, porewater methane concentrations were collected at multiple depths near trees. Abiotic parameters such as soil temperature, soil moisture, water potential, and depth to groundwater were monitored using a wireless sensor network. Upland emissions from tree stems were as high as 14.6 umoles CH4 m-2 hr-1 while the soil uptake was -1.5 umoles CH4 m-2 hr-1. These results demonstrate that tree methane emissions and soil methane uptake can occur simultaneously in a mesic forest. Factors controlling methane emissions were soil temperature, soil moisture, and depth to groundwater. Based on our preliminary data, tree mediated methane emissions may be offsetting the soil methane sink of upland forests by 20 to 30%. Future methane budgets and climate models will need to include tree fluxes and the parameters that control methane emissions for accurate accounting and predictions.

Pitz, S.; Megonigal, P.; Schile, L. M.; Szlavecz, K. A.; King, K.

2013-12-01

408

A characterization of the set of species trees that produce anomalous ranked gene trees.  

PubMed

Ranked gene trees, which consider both the gene tree topology and the sequence in which gene lineages separate, can potentially provide a new source of information for use in modeling genealogies and performing inference of species trees. Recently,we have calculated the probability distribution of ranked gene trees under the standard multispecies coalescent model for the evolution of gene lineages along the branches of a fixed species tree, demonstrating the existence of anomalous ranked gene trees (ARGTs), in which a ranked gene tree that does not match the ranked species tree can have greater probability under the model than the matching ranked gene tree. Here, we fully characterize the set of unranked species tree topologies that give rise to ARGTs, showing that this set contains all species tree topologies with five or more taxa, with the exceptions of caterpillars and pseudocaterpillars. The results have implications for the use of ranked gene trees in phylogenetic inference. PMID:22868677

Degnan, James H; Rosenberg, Noah A; Stadler, Tanja

2012-01-01

409

arXiv:cs.DS/0205045 Balancing Minimum Spanning Trees  

E-print Network

arXiv:cs.DS/0205045 v1 18 May 2002 Balancing Minimum Spanning Trees and Shortest-Path Trees Samir-path tree and a minimum spanning tree. The algorithm provides a continuous trade-o#11;: given the two trees of the tree is at most 1 + p 2= times the weight of a minimum spanning tree. Our algorithm runs in linear

Raghavachari, Balaji

410

Lecture 10: Minimum Spanning Trees and Prim's Algorithm  

E-print Network

Lecture 10: Minimum Spanning Trees and Prim's Algorithm CLRS Chapter 23 Outline of this Lecture · Spanning trees and minimum spanning trees. · The minimum spanning tree (MST) problem. · Prim's algorithm. w=74 Minimum spanning tree 4 #12;Minimum Spanning Trees A Minimum Spanning Tree in an undirected

Golin, Mordecai J.

411

Splay trees: a reweighing lemma and a proof of competitiveness vs. dynamic balanced trees  

Microsoft Academic Search

We give a new lemma (dynamic reweighing) about splay trees and we define a class of dynamically self-adjusted trees (parametrically balanced) wide enough to include BB(?), AVL, rank-balanced and B-trees. Using our lemma we prove that splay trees are competitive to any such class of dynamic trees—noticing that so far splay trees had been proven competitive only w.r.t. static structures

George F. Georgakopoulos

2004-01-01

412

A Model In Which There Are Jech Kunen Trees But There Are No Kurepa Trees 1  

E-print Network

A Model In Which There Are Jech Kunen Trees But There Are No Kurepa Trees 1 Saharon Shelah2 and Renling Jin Abstract By an !1 tree we mean a tree of power !1 and height !1. We call an !1 tree a Jech Kunen tree if it has many branches for some strictly between !1 and 2!1 . In this paper we construct

Jin, Renling

413

Recognition of a Spanning Tree of Directed Acyclic Graphs by Tree Automata  

Microsoft Academic Search

In this paper, we study tree automata for directed acyclic graphs (DAGs). We define the movement of a tree automaton on a\\u000a DAG so that a DAG is accepted by a tree automaton if and only if a DAG has a spanning tree accepted by a tree automaton. The\\u000a NP-completeness of the membership problem of DAGs for a tree automaton

Akio Fujiyoshi

2009-01-01

414

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

415

Decision Tree Induction Based on Efficient Tree Restructuring1 Paul E. Utgoff utgoff@cs.umass.edu  

E-print Network

Decision Tree Induction Based on Efficient Tree Restructuring1 Paul E. Utgoff utgoff to restructure a decision tree efficiently enables a variety of ap- proaches to decision tree induction incremental tree induction (ITI), and the other being non-incremental tree induction using a measure of tree

Massachusetts at Amherst, University of

416

Decision Tree Induction Based on Efficient Tree Restructuring 1 Paul E. Utgoff utgoff@cs.umass.edu  

E-print Network

Decision Tree Induction Based on Efficient Tree Restructuring 1 Paul E. Utgoff utgoff to restructure a decision tree efficiently enables a variety of ap­ proaches to decision tree induction incremental tree induction (ITI), and the other being non­incremental tree induction using a measure of tree

Massachusetts at Amherst, University of

417

Properties of consensus methods for inferring species trees from gene trees.  

PubMed

Consensus methods provide a useful strategy for summarizing information from a collection of gene trees. An important application of consensus methods is to combine gene trees to estimate a species tree. To investigate the theoretical properties of consensus trees that would be obtained from large numbers of loci evolving according to a basic evolutionary model, we construct consensus trees from rooted gene trees that occur in proportion to gene-tree probabilities derived from coalescent theory. We consider majority-rule, rooted triple (R(*)), and greedy consensus trees obtained from known, rooted gene trees, both in the asymptotic case as numbers of gene trees approach infinity and for finite numbers of genes. Our results show that for some combinations of species-tree branch lengths, increasing the number of independent loci can make the rooted majority-rule consensus tree more likely to be at least partially unresolved. However, the probability that the R(*) consensus tree has the species-tree topology approaches 1 as the number of gene trees approaches infinity. Although the greedy consensus algorithm can be the quickest to converge on the correct species-tree topology when increasing the number of gene trees, it can also be positively misleading. The majority-rule consensus tree is not a misleading estimator of the species-tree topology, and the R(*) consensus tree is a statistically consistent estimator of the species-tree topology. Our results therefore suggest a method for using multiple loci to infer the species-tree topology, even when it is discordant with the most likely gene tree. PMID:20525567

Degnan, James H; DeGiorgio, Michael; Bryant, David; Rosenberg, Noah A

2009-02-01

418

Connections and activities of interest between the State of Ohio and Japan Prepared by the Institute for Japanese Studies at The Ohio State University, http://japan.osu.edu japan@osu.edu  

E-print Network

of bonsai, the Japanese art of miniature trees, in the Old World setting of German Village's historic possesses important examples in metalwork, lacquer, sculpture, painting, and ceramics from both Japan

Jones, Michelle

419

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

420

Cache Oblivious Search Trees via Binary Trees of Small Height  

E-print Network

for laying out a search tree in memory. 1 Introduction Modern computers contain a hierarchy of memory levels, with each level acting as a cache for the next. Typical components of the memory hierarchy are: registers widely used of these is the I/O model of Aggarwal and Vitter [1], which assumes a memory hierarchy

Riko Jacob

421

CONTEXT-TREE WEIGHTING FOR EXTENDED TREE SOURCES  

Microsoft Academic Search

At the ISIT'95 Suzuki (1) presented a context weighting algorithm that covered a more general class of sources than the context-tree weighting method, at the cost of some extra complexity. Here his algorithm will be compared to an algorithm, that covers the same model class. Most modern universal source coding algorithms are based on statistical tech- niques. These algorithms consist

Paul A. J. Volf; Frans M. J. Willems

422

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

423

Estimating optimal species trees from incomplete gene trees under deep coalescence.  

PubMed

The estimation of species trees typically involves the estimation of trees and alignments on many different genes, so that the species tree can be based on many different parts of the genome. This kind of phylogenomic approach to species tree estimation has the potential to produce more accurate species tree estimates, especially when gene trees can differ from the species tree due to processes such as incomplete lineage sorting (ILS), gene duplication and loss, and horizontal gene transfer. Because ILS (also called "deep coalescence") is a frequent problem in systematics, many methods have been developed to estimate species trees from gene trees or alignments that specifically take ILS into consideration. In this paper we consider the problem of estimating species trees from gene trees and alignments for the general case where the gene trees and alignments can be incomplete, which means that not all the genes contain sequences for all the species. We formalize optimization problems for this context and prove theoretical results for these problems. We also present the results of a simulation study evaluating existing methods for estimating species trees from incomplete gene trees. Our simulation study shows that *BEAST, a statistical method for estimating species trees from gene sequence alignments, produces by far the most accurate species trees. However, *BEAST can only be run on small datasets. The second most accurate method, MRP (a standard supertree method), can analyze very large datasets and produces very good trees, making MRP a potentially acceptable alternative to *BEAST for large datasets. PMID:22697236

Bayzid, Md Shamsuzzoha; Warnow, Tandy

2012-06-01

424

Recursive algorithms for phylogenetic tree counting  

PubMed Central

Background In Bayesian phylogenetic inference we are interested in distributions over a space of trees. The number of trees in a tree space is an important characteristic of the space and is useful for specifying prior distributions. When all samples come from the same time point and no prior information available on divergence times, the tree counting problem is easy. However, when fossil evidence is used in the inference to constrain the tree or data are sampled serially, new tree spaces arise and counting the number of trees is more difficult. Results We describe an algorithm that is polynomial in the number of sampled individuals for counting of resolutions of a constraint tree assuming that the number of constraints is fixed. We generalise this algorithm to counting resolutions of a fully ranked constraint tree. We describe a quadratic algorithm for counting the number of possible fully ranked trees on n sampled individuals. We introduce a new type of tree, called a fully ranked tree with sampled ancestors, and describe a cubic time algorithm for counting the number of such trees on n sampled individuals. Conclusions These algorithms should be employed for Bayesian Markov chain Monte Carlo inference when fossil data are included or data are serially sampled. PMID:24164709

2013-01-01

425

The most parsimonious tree for random data.  

PubMed

Applying a method to reconstruct a phylogenetic tree from random data provides a way to detect whether that method has an inherent bias towards certain tree 'shapes'. For maximum parsimony, applied to a sequence of random 2-state data, each possible binary phylogenetic tree has exactly the same distribution for its parsimony score. Despite this pleasing and slightly surprising symmetry, some binary phylogenetic trees are more likely than others to be a most parsimonious (MP) tree for a sequence of k such characters, as we show. For k=2, and unrooted binary trees on six taxa, any tree with a caterpillar shape has a higher chance of being an MP tree than any tree with a symmetric shape. On the other hand, if we take any two binary trees, on any number of taxa, we prove that this bias between the two trees vanishes as the number of characters k grows. However, again there is a twist: MP trees on six taxa for k=2 random binary characters are more likely to have certain shapes than a uniform distribution on binary phylogenetic trees predicts. Moreover, this shape bias appears, from simulations, to be more pronounced for larger values of k. PMID:25079136

Fischer, Mareike; Galla, Michelle; Herbst, Lina; Steel, Mike

2014-11-01

426

SELECTING AND TESTING STREET TREE CULTIVARS  

Microsoft Academic Search

ABSTRAC T- - To improve street trees through better selection of species 1 and cultivars is an important goal of the Municipal Tree Restoration Program . Communities have been assisted by publishing \\

HENRY D. GERHOLD

427

Secondhand Trees, Firsthand Learning. Holiday Evergreens Revitalized.  

ERIC Educational Resources Information Center

Described is an activity that uses discarded evergreen trees from Christmas. Tree age and growth characteristics are investigated by looking at the number of whorls and rings of the trunks. Extensions and follow-up activities are included. (KR)

Graves, C. John

1990-01-01

428

Generating Functions for Multi-labeled Trees  

PubMed Central

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

Erd?s, P.L.; Johnson, V.; Moulton, V.

2012-01-01

429

The Tree of Animal Life  

ERIC Educational Resources Information Center

In this article, the author describes a short activity which introduces third- to fifth-grade students to animal classification. The Tree of Animal Life activity is a simple, sorting exercise that can help them see a bigger picture. The activity sets the stage for learning about animal taxonomy and introduces the characteristics of various animal…

Braude, Stan

2007-01-01

430

The Trees that surround us  

NASA Astrophysics Data System (ADS)

In our school the activities linked with sciences are developed in a partnership with other school subjects. Interdisciplinary projects are always valued from beginning to end of a project. It is common for teachers of different areas to work together in a Science project. Research of English written articles is very important not only for the development of our students' scientific literacy but also as a way of widening knowledge and a view on different perspectives of life instead of being limited to research of any articles in Portuguese language. In this study we are going to collect data about the predominant tree species in the region, especially the invasive trees from the acacia species, the native tree species and the commercial species. We are going to study the reasons for the appearance of each species and draw a chart of soil occupation in the council. This chart will also allow the study of the distribution and use of land for each tree species. This research work is the first stage for a contribution to warn the town council of the dangers of the invasive species to the future economy of the council.

Costa, M. E. G.; Rodrigues, M. A. S.

2012-04-01

431

Compartmentalization of Decay in Trees.  

ERIC Educational Resources Information Center

Unlike animals, which heal, trees compartmentalize by setting boundaries that resist the spread of invading microorganisms. Discusses the creation of new walls by anatomical and chemical means in response to death of a branch or pruning. Points out that genetic control of compartmentalization has resulted from evolution of resistant species. (DH)

Shigo, Alex L.

1985-01-01

432

Dependency Tree Automata Colin Stirling  

E-print Network

.r.t. finite value sets) [Ghica + McCusker 2000, Ong 2002, . . .] #12;Active research goal: transfer of idealized Algol (w.r.t. finite value sets) [Ghica + McCusker 2000, Ong 2002, . . .] 2. Model checking higher-order trees [Knapik + Niwinski + Urzyczyn 2002, Caucal 2002, Ong 2006, Hague + Murawski + Ong +Serre, 2008

Stirling, Colin

433

Electric Trees and Pond Creatures.  

ERIC Educational Resources Information Center

Two learning activities are presented to develop observation and classification skills at the elementary level. The first is an electric box that associates tree names with leaf and bark specimens, and the second is a pond water observation and slide preparation activity. (BB)

Weaver, Helen; Hounshell, Paul B.

1978-01-01

434

The Gift of the Tree  

ERIC Educational Resources Information Center

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-depth interdisciplinary lesson for her sixth-grade students without diluting the science. Through this…

Jones, Marla Wagner

2009-01-01

435

The Tree of Life Project  

ERIC Educational Resources Information Center

Middle-school students are just beginning to recognize their place in the world. That is why this author believes it is important to incorporate their world into their art. In this article, the author discusses the "Tree of Life" project, which she developed for her students in order to make them aware of various environmental issues, and how to…

Milbrath, Sherry

2009-01-01

436

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

437

Remembering Without Memory: Tree Exploration  

E-print Network

. In the effort to understand the algorithmic limitations of computing by a swarm of robots, the research has.1007/978-3-540-69355-0_5 #12;problem to be solved by a swarm of robots. In the investigations, three models are commonly usedRemembering Without Memory: Tree Exploration by Asynchronous Oblivious Robots Paola Flocchini1

Paris-Sud XI, Université de

438

Not Just a Fall Tree  

ERIC Educational Resources Information Center

Trees burst with color in the northern states. Autumn leaves dust the ground. Painting the fall landscape is nothing new. Teachers have been doing it in classrooms for decades. The approach, however, can make the difference between whether the fall landscape is simply painting for fun, or a real learning experience. Students learn best when they…

Miller-Hewes, Kathy A.

2004-01-01

439

Seasonal Changes of a Tree  

NSDL National Science Digital Library

This activity is a year long project observing the changes in a specific tree. It includes using all the senses in the observation and making two different booklets to record what we observe. It also includes several picture story books that enhance the lesson.

Karen Johnson

440

Cedar Tree in Bryce Canyon  

USGS Multimedia Gallery

A cedar tree in Bryce Canyon National Park. Bryce Canyon is a unique sandstone formation in southern Utah. It is home to a large number of hoodoos, which are oddly shaped pillars of rock that formed due to different erosion rates for the dolomite that caps them and the sandstone that forms their ba...

441

Can Children Read Evolutionary Trees?  

ERIC Educational Resources Information Center

Representations of the "tree of life" such as cladograms show the history of lineages and their relationships. They are increasingly found in formal and informal learning settings. Unfortunately, there is evidence that these representations can be challenging to interpret correctly. This study explored the question of whether children aged 7-11…

Ainsworth, Shaaron; Saffer, Jessica

2013-01-01

442

Dynamical Systems Trees Tony Jebara  

E-print Network

extended traditional dynamical systems, improving upon classical linear Kalman filters and hidden Markov dynamical systems (SLDSs) that combine Kalman filters and HMMs [9, 1, 7, 5] to obtain nonlinear continuous interact as communities and sub-communities in a tree structure that is un- rolled in time. To accommodate

Jebara, Tony

443

MYCOTOXINS IN EDIBLE TREE NUTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tree nuts (almonds, pistachios, and walnuts) are an exceptionally valuable crop, especially in California, with an aggregate value approaching $3.5 billion. Much of this economic value comes from overseas markets, with up to 60% of the crop being exported. The product can be contaminated with aflat...

444

Stable isotopes in tree rings  

Microsoft Academic Search

Stable isotopes in tree rings could provide palaeoclimate reconstructions with perfect annual resolution and statistically defined confidence limits. Recent advances make the approach viable for non-specialist laboratories. The relevant literature is, however, spread across several disciplines, with common problems approached in different ways. Here we provide the first overview of isotope dendroclimatology, explaining the underlying theory and describing the steps

Danny McCarroll; Neil J. Loader

2004-01-01

445

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.

446

Feathered Hollow in Living Tree  

USGS Multimedia Gallery

Hollow in living tree in gallery forest of tributary to Tebicuary river. Grey feathers stuck along bottom of entrance suggest that it may be used by a bird. Paraguay is home to at least 589 breeding bird species and 120 migratory bird species. The Ñeembucú Region is typified by extensi...

447

Logistic Model Trees + Niels Landwehr  

E-print Network

Logistic Model Trees + Niels Landwehr Institute for Computer Science, University of Freiburg for classification problems, using logistic regression instead of linear regression. We use a stagewise fitting process to construct the logistic regression models that can select relevant attributes in the data

Frank, Eibe

448

Logistic Model Trees Niels Landwehr  

E-print Network

Logistic Model Trees Niels Landwehr Institute for Computer Science, University of Freiburg for classification problems, using logistic regression instead of linear regression. We use a stagewise fitting process to construct the logistic regression models that can select relevant attributes in the data

Frank, Eibe

449

Statistical Methods for Evolutionary Trees  

PubMed Central

In 1963 and 1964, L. L. Cavalli-Sforza and A. W. F. Edwards introduced novel methods for computing evolutionary trees from genetical data, initially for human populations from blood-group gene frequencies. The most important development was their introduction of statistical methods of estimation applied to stochastic models of evolution. PMID:19797062

Edwards, A. W. F.

2009-01-01

450

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.

New York College of Environmental Science and Forestry

451

Chopping Down the Cherry Tree.  

ERIC Educational Resources Information Center

Attempts once again to put to rest the infamous "I cannot tell a lie" episode involving George Washington and a downed cherry tree. Appends an editor's note that states that William Bennett's "The Children's Book of Virtues" which perpetuates this infamous piece of "fakelore." (RS)

Griswold, Jerry

1995-01-01

452

Selecting Landscape Plants: Shade Trees  

E-print Network

Selecting Landscape Plants: Shade Trees Diane Relf, Extension Specialist, Horticulture, Virginia for any landscape plan. They set the stage for the entire home grounds design. The type used. Many will live and enhance the landscape for 100 or more years if they are given a chance. Because

Liskiewicz, Maciej

453

A Bayes Evaluation Criterion for Decision Trees  

Microsoft Academic Search

\\u000a We present a new evaluation criterion for the induction of decision trees. We exploit a parameter-free Bayesian approach and\\u000a propose an analytic formula for the evaluation of the posterior probability of a decision tree given the data. We thus transform\\u000a the training problem into an optimization problem in the space of decision tree models, and search for the best tree,

Nicolas Voisine; Marc Boullé; Carine Hue

2009-01-01

454

Texas Wholesale Market for Christmas Trees.  

E-print Network

Wholesale Market for 7 :. @EXAS A&M UNIVERSITY . TEXAS AGRICULTURAL EXPERIMENT STATION R. E. Patterson, Director, College Station, Texas trees might capture as much as one-half of the more than 2 million Texas evergreen tree market. Wl...~olesale Christmas tree markets for Dallas, Houston and San Antonio were investigated during the 1962 Holiday Season to determine potential outlets for locally grown trees. The investigation was limited to species which could be grown in at least a part...

Sorensen, H. B. (Harold B.); Smith, W. A.

1964-01-01

455

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

456

CS 331, Fall 2013 Minimum Spanning Trees  

E-print Network

CS 331, Fall 2013 Minimum Spanning Trees Tandy Warnow (most slides by Richard Anderson from Univ Washington) #12;Minimum Spanning Tree a b c s e g f 9 2 13 6 4 11 5 7 20 14 t u v 15 10 1 8 12 16 22 17 3 #12;Greedy Algorithms for Minimum Spanning Tree · Extend a tree by including the cheapest outgoing edge · Add

Warnow,Tandy

457

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.

458

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.

459

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.

Erica Bigio

460

WHAT MAKES A BIG TREE SPECIAL? INSIGHTS FROM THE CHICAGOLAND TREEMENDOUS TREES PROGRAM  

Microsoft Academic Search

In 1995, a local version of the American Forests big trees program (Treemendous Trees) was initiated in the Chicago area by Openlands Project and the Morton Arboretum. In addition to the numerical information about tree sizes required on the nomination form, many participants attached notes and sometimes lengthy letters that detailed various aspects of the nominated trees. A qualitative analysis

Susan C. Barro; Paul H. Gobster; Herbert W. Schroeder; Stephen M. Bartram

1997-01-01

461

Using Tree Rings to Predict the Response of Tree Growth to Climate  

E-print Network

the International Tree-Ring Data Bank (ITRDB). Comparing annual tree-ring- width data from 1097 sites). The geographic distribution of climate change, however, was far from uniform within the continental United StatesUsing Tree Rings to Predict the Response of Tree Growth to Climate Change in the Continental United

Williams, Park

462

TreeDT: Tree Pattern Mining for Gene Mapping Petteri Sevon, Hannu Toivonen, and Vesa Ollikainen  

E-print Network

TreeDT: Tree Pattern Mining for Gene Mapping Petteri Sevon, Hannu Toivonen, and Vesa Ollikainen Abstract--We describe TreeDT, a novel association-based gene mapping method. Given a set of disease-associated haplotypes and a set of control haplotypes, TreeDT predicts likely locations of a disease susceptibility gene

Toivonen, Hannu

463

Street tree valuation systems The Capital Asset Value for Amenity Trees (CAVAT) scheme provides a method  

E-print Network

Street tree valuation systems The Capital Asset Value for Amenity Trees (CAVAT) scheme provides a method for managing trees as public assets in London. A literature and methodological review was commissioned to assess approaches to estimating the amenity value of street trees to feed into Forestry

464

ForPeerReview Tree diversity enhances tree transpiration in a Panamanian  

E-print Network

ForPeerReview Tree diversity enhances tree transpiration in a Panamanian forest plantation Journal-species stands, monoculture, native species, plot transpiration, selection effect Journal of Applied Ecology #12;ForPeerReview 1 Tree diversity enhances tree transpiration in a Panamanian forest plantation1 2

Bermingham, Eldredge

465

The Asymmetric Median Tree - A New model for Building Consensus Trees  

Microsoft Academic Search

Inferring the consensus of a set of different evolutionary trees for a given species set is a well-studied problem, for which several different models have been proposed. In this paper, we propose a new optimization problem for consensus tree construction, which we call the asymmetric median tree, (AMT). Our main theoretical result is the equivalence between the asymmetric median tree

Cynthia A. Phillips; Tandy J. Warnow

1996-01-01

466

Rounding via trees: deterministic approximation algorithms for group Steiner trees and k -median  

Microsoft Academic Search

Most optimization problems on an undirected graphreduce in complexity when restricted to instanceson a tree. A recent result [3] for probabilisticallyapproximating graph metrics by trees such that noedge stretches (in an expected sense) by more thana factor of O(log2n) has resulted in several approximationalgorithms which exploit the ease of solvingproblems on trees. The tree construction in [3] is inherentlyrandomized and

Moses Charikar; Chandra Chekuri; Ashish Goel; Sudipto Guha

1998-01-01

467

Reconciling a Gene Tree to a Species Tree Under the Duplication Paola Bonizzoni  

E-print Network

) for the extant species, the first step constructs a gene tree representing the relationships among the sequencesReconciling a Gene Tree to a Species Tree Under the Duplication Cost Model Paola Bonizzoni Gianluca from evolutionary trees representing the relationships between distinct gene families is of great

Della Vedova, Gianluca

468

The probability distribution of ranked gene trees on a species tree James H. Degnan a,  

E-print Network

of applications. First, it provides a mathematical basis for studying the properties of gene trees in a standardThe probability distribution of ranked gene trees on a species tree James H. Degnan a, , Noah A Accepted 21 October 2011 Available online 31 October 2011 Keywords: Anomalous gene trees Coalescent

Rosenberg, Noah

469

The Trees and the Forest: Characterization of complex brain networks with minimum spanning trees.  

E-print Network

The Trees and the Forest: Characterization of complex brain networks with minimum spanning trees. C to this problem is to represent brain networks by a minimum spanning tree (MST), a unique acyclic subgraph networks, Graph theory, minimum spanning tree, functional connectivity, EEG, MEG #12; 3 Table

Van Mieghem, Piet

470

Inferring Species Trees Directly from Biallelic Genetic Markers: Bypassing Gene Trees in a Full Coalescent Analysis  

E-print Network

Inferring Species Trees Directly from Biallelic Genetic Markers: Bypassing Gene Trees in a Full framework for estimating species trees and species demograph- ics from genetic markers. However, practical trees possible for each genetic marker. Here we describe a polynomial-time algorithm that computes

Rosenberg, Noah

471

Discordance of Species Trees with Their Most Likely Gene Trees: A Unifying Principle  

E-print Network

Letter Discordance of Species Trees with Their Most Likely Gene Trees: A Unifying Principle Noah A@stanford.edu. Associate editor: Barbara Holland Abstract A labeled gene tree topology that disagrees with a labeled species tree topology is said to be anomalous if it is more probable under a coalescent model for gene

Rosenberg, Noah

472

DOES TREE HARDNESS INFLUENCE NEST-TREE SELECTION BY PRIMARY CAVITY NESTERS?  

Microsoft Academic Search

may vary among bird species, causing nest-tree selection to vary among excavator species. We examined use of quaking aspens (Populus tremuloides) for nest trees as a function of tree hardness in four species of woodpeckers: Williamson's Sapsucker (Sphyrapicus thyroideus), Red-naped Sapsucker (S. nuchalis), Downy Woodpecker (Picoides pubescens), and Hairy Woodpecker (P. villosus). Hardness of trees was measured at 95 nest

JAKE SCHEPPS; STEVE LOHR; THOMAS E. MARTIN

473

Picking a tree: habitat use by the tree agama, Acanthocercus atricollis atricollis, in South Africa  

Microsoft Academic Search

We studied tree agama (Acanthocercus a. atricollis) habitat use in the Magaliesberg mountain range in northern South Africa using sightings of marked individuals, and in a few cases, radio-telemetry. Acanthocercus a. atricollis preferentially selected thorn trees (46%; Acacia karroo), followed by common sugarbush (10%; Protea caffra) and dead trees (9%). The type of tree selected was unrelated to lizard age

Leeann T. Reaney; Martin J. Whiting

2003-01-01

474

trees.sty: A Macro for Drawing Binary or Ternary Trees  

E-print Network

trees.sty: A Macro for Drawing Binary or Ternary Trees april 1990 The following macros let you draw a (binary or ternary) tree of any size. For each will give you some ideas on designi* *ng similar things for, e.g., digital circuits. Trees

Mintmire, John W.

475

High-Tech Trees: Colorado State University, recently recognized as aTree Campus USA by  

E-print Network

High-Tech Trees: Background Colorado State University, recently recognized as aTree Campus USA by the Arbor Day Foundation, possesses a diverse and rich variety of trees on its campuses. CSU Facilities has maintained and inventoried these trees over the years, with periodic support from students in horticulture

476

A Characterization of the Set of Species Trees that Produce Anomalous Ranked Gene Trees  

E-print Network

A Characterization of the Set of Species Trees that Produce Anomalous Ranked Gene Trees James H. Degnan, Noah A. Rosenberg, and Tanja Stadler Abstract--Ranked gene trees, which consider both the gene tree topology and the sequence in which gene lineages separate, can potentially provide a new source

Rosenberg, Noah

477

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

478

Effect of tree channel conductivity on electrical tree shape and breakdown in XLPE cable insulation samples  

Microsoft Academic Search

The results of an investigation into electrical tree growth in XLPE cable insulation using an embedded needle electrode are reported for a range of voltages from 9 kV rms to 27 kV rms. The partial discharge (PD) activity and tree structures were measured simultaneously throughout the tree growth and the trees were recorded from initiation up to and including the

Xiangrong Chen; Yang Xu; Xiaolong Cao; S. J. Dodd; L. A. Dissado

2011-01-01

479

On Reconstructing Species Trees From Gene Trees In Term Of Duplications And Losses  

E-print Network

it. Similarly, in a species tree, an ancient species is defined by the con­ temporary speciesOn Reconstructing Species Trees From Gene Trees In Term Of Duplications And Losses Bin Ma \\Lambda ancestors mapping, the duplication and mutation costs, and the complexity of finding a species tree from

Page, Roderic

480

On Reconstructing Species Trees From Gene Trees In Term Of Duplications And Losses  

E-print Network

it. Similarly, in a species tree, an ancient species is de ned by the con- temporary speciesOn Reconstructing Species Trees From Gene Trees In Term Of Duplications And Losses Bin Ma , Ming ancestors mapping, the duplication and mutation costs, and the complexity of nding a species tree from gene

Page, Roderic

481

Portland State University CSAR Street Trees in the Urban Forest Canopy STREET TREES IN  

E-print Network

Portland State University ­ CSAR Street Trees in the Urban Forest Canopy STREET TREES IN THE URBAN Forest Canopy Contents ACKNOWLEDGMENTS SUMMARY Trees in the Urban Environment-27 #12;Portland State University ­ CSAR Street Trees in the Urban Forest Canopy ACKNOWLEDGMENTS

Poracsky, Joseph

482

Hardwood Tree Improvement and Regeneration Center  

E-print Network

FNR-213 Hardwood Tree Improvement and Regeneration Center North Central Research Station USDA Forest Service Department of Forestry and Natural Resources Purdue University Designing Hardwood Tree Woody plants can be of value to many wildlife species. The species of tree or shrub, or the location

483

TREE MAINTENANCE AND REMOVAL Table Of Contents  

E-print Network

EM 385-1-1 XX Sep 13 i Section 31 TREE MAINTENANCE AND REMOVAL Table Of Contents Section: Page 31.A General................... ......................................................31-1 31.B Tree Climbing.................................31-14 #12;EM 385-1-1 XX Sep 13 31-1 SECTION 31 TREE MAINTENANCE AND REMOVAL 31. A GENERAL 31.A.01

US Army Corps of Engineers

484

Dynamic Segment Trees for Ranges and Prefixes  

Microsoft Academic Search

In this paper, we develop a segment tree data structure for solving dynamic table lookup problems. The proposed dynamic segment tree (DST) uses all distinct endpoints of ranges as the keys based on a new range endpoint scheme. The new endpoint scheme generates fewer endpoints than the traditional endpoint scheme. DST is implemented as a balanced binary search tree augmented

Yeim-kuan Chang; Yung-chieh Lin

2007-01-01

485

TREES OF GENES IN POPULATIONS Joseph Felsenstein  

E-print Network

1 TREES OF GENES IN POPULATIONS Joseph Felsenstein Abstract Trees of ancestry of copies of genes appears thin. If each of these thin lines truly contained only one copy of this gene's sequence, we would and more important to evolutionary genetics. #12;4 Trees of genes in populations To explain how population

Borenstein, Elhanan

486

Fuzzy quadratic minimum spanning tree problem  

E-print Network

Fuzzy quadratic minimum spanning tree problem Jinwu Gao *, Mei Lu Department of Mathematical the effectiveness of the genetic algorithm. Ã? 2004 Published by Elsevier Inc. Keywords: Minimum spanning tree; Fuzzy programming; Genetic algorithm; Credibility measure 1. Introduction The minimum spanning tree (MST) problem

Lu, Mei

487

Approximating Spanning Tree with Weighted Inner Nodes  

E-print Network

a minimum spanning tree with both edge weights and inner node (non-leaf node) weights. This problem is NP is the maximum degree of the graph. Keywords: Minimum spanning tree, approximation algorithm, NP-hard 1 Introduction 1.1 Problem Statement Minimum spanning trees have been widely studied and many efficient

488

Distinguished The Minimum Label Spanning Tree  

E-print Network

Distinguished 2006 Series The Minimum Label Spanning Tree Problem: Illustrating the Power a connected, undirected graph G whose edges are labeled (or colored), the minimum label spanning tree (MLST) problem seeks a spanning tree on G with the minimum number of distinct labels (or colors). The MLST

Aydilek, Ahmet

489

Brief Contributions________________________________________________________________________________ Distributed Minimum Spanning Tree  

E-print Network

________________________________________________________________________________ Distributed Minimum Spanning Tree Maintenance for Transient Node Failures Paola Flocchini, T. Mesa Enriquez, the computation takes place on the minimum-cost spanning tree (MST) of the network G; unfortunately, a single link consider for the first time the problem of computing all the replacement minimum-cost spanning trees

Prencipe, Giuseppe

490

Multiple criteria minimum spanning trees Pedro Cardoso  

E-print Network

Multiple criteria minimum spanning trees Pedro Cardoso M´ario Jesus ´Alberto M´arquez Abstract The NP multiple criteria minimum spanning tree as several applications into the network design problems criteria minimum spanning trees. There are several geometric network design and application problems

Coello, Carlos A. Coello

491

Parametric and Kinetic Minimum Spanning Trees  

Microsoft Academic Search

We consider the parametric minimum spanning tree problem, in which we are given a graph with edge weights that are linear functions of a parameter‚ and wish to com- pute the sequence of minimum spanning trees generated as‚ varies. We also consider the kinetic minimum spanning tree problem, in which‚ represents time and the graph is subject in addition to

Pankaj K. Agarwal; David Eppstein; Leonidas J. Guibas; Monika Rauch Henzinger

1998-01-01

492

Maintaining Minimum Spanning Trees in Dynamic Graphs  

E-print Network

Maintaining Minimum Spanning Trees in Dynamic Graphs Monika R. Henzinger 1 and Valerie King 2 1 for maintaining a minimum spanning tree in time o( p n) per operation. To be precise, the algorithm uses O(n 1 We consider the problem of maintaining a minimum spanning tree during an arbitrary sequence of edge

King, Valerie

493

a buyer's guide Trees for Conservation  

E-print Network

a buyer's guide Trees for Conservation #12;ii Many thanks to Dennis Will, Dan Wand, Greg Morgenson #115-1196 The Colorado State Forest Service tree program enables farmers, ranchers and rural landowners to obtain trees at nominal cost. The program's aim is to encourage landowners to plant new forests

494

Merging BSP trees yields polyhedral set operations  

Microsoft Academic Search

BSP trees have been shown to provide an effective representation of polyhedra through the use of spatial subdivision, and are an alternative to the topologically based b-reps. While bsp tree algorithms are known for a number of important operations, such as rendering, no previous work on bsp trees has provided the capability of performing boolean set operations between two objects

Bruce F. Naylor; John Amanatides; William C. Thibault

1990-01-01

495

Decision Tree Validation: A Comprehensive Approach  

Microsoft Academic Search

Ever since the availability of data mining tools, decision trees have been popular because they are simple to use and easy to interpret. Producing decision trees is straightforward, but evaluating them can be a challenge. In predictive modeling, overfitting is always a danger. A good decision tree must generalize the trends in the data, and this is why the assessment

Sylvain Tremblay

496

Malcolm Guite The Magic Apple Tree  

E-print Network

Malcolm Guite The Magic Apple Tree Someday make a journey through the rain Through sodden streets in darkening December A journey to the magic apple tree. And journey also, darkling, through your past Journey records. You glimpsed it once within the garden wall, The image of an ancient apple tree, The fall

Robertson, Stephen

497

Hardwood Tree Improvement and Regeneration Center  

E-print Network

. Herbicide Injury Herbicides applied for weed control can damage and even kill hardwood trees. Young trees-lethal herbicide damage usually occurs when herbicide sprays drift onto hardwood seedlings or when herbicides matter also can affect how young trees respond to herbicides. Symptoms of herbicide damage include

498

A general bijective algorithm for trees.  

PubMed Central

Trees are combinatorial structures that arise naturally in diverse applications. They occur in branching decision structures, taxonomy, computer languages, combinatiorial optimization, parsing of sentences, and cluster expansions of statistical mechanics. Intuitively, a tree is a collection of branches connected at nodes. Formally, it can be defined as a connected graph without cycles. Schroder trees, introduced in this paper, are a class of trees for which the set of subtrees at any vertex is endowed with the structure of ordered partitions. An ordered partition is a partition of a set in which the blocks are linearly ordered. Labeled rooted trees and labeled planed trees are both special classes of Schroder trees. The main result gives a bijection between Schroder trees and forests of small trees--namely, rooted trees of height one. Using this bijection, it is easy to encode a Schroder tree by a sequence of integers. Several classical algorithms for trees, including a combinatorial proof of the Lagrange inversion formula, are immediate consequences of this bijection. PMID:11607133

Chen, W Y

1990-01-01

499

Genomics of Tropical Fruit Tree Crops  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genetic improvement of tropical fruit trees is limited when compared to progress achieved in temperate fruit trees and annual crops. Tropical fruit tree breeding programs require significant resources to develop new cultivars that are adapted to modern shipping and storage requirements. The use...

500

CSCI2010U Laboratory #8 Binary Trees  

E-print Network

CSCI2010U ­ Laboratory #8 Binary Trees Introduction This lab has one activity that relates to programming binary trees. To complete this lab you will need to visit the course website and download the required Lab 8 resources: · BTNode.java · BinaryTree.java · Demo.java Activity 1: Add a new method called

Bradbury, Jeremy S.