971 resultados para Decision trees


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This paper sets out to identify the initial positions of the different decisionmakers who intervene in a group decision making process with a reducednumber of actors, and to establish possible consensus paths between theseactors. As a methodological support, it employs one of the most widely-knownmulticriteria decision techniques, namely, the Analytic Hierarchy Process(AHP). Assuming that the judgements elicited by the decision makers follow theso-called multiplicative model (Crawford and Williams, 1985; Altuzarra et al.,1997; Laininen and Hämäläinen, 2003) with log-normal errors and unknownvariance, a Bayesian approach is used in the estimation of the relative prioritiesof the alternatives being compared. These priorities, estimated by way of themedian of the posterior distribution and normalised in a distributive manner(priorities add up to one), are a clear example of compositional data that will beused in the search for consensus between the actors involved in the resolution ofthe problem through the use of Multidimensional Scaling tools

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This paper presents a procedure that allows us to determine the preference structures(PS) associated to each of the different groups of actors that can be identified in a groupdecision making problem with a large number of individuals. To that end, it makesuse of the Analytic Hierarchy Process (AHP) (Saaty, 1980) as the technique to solvediscrete multicriteria decision making problems. This technique permits the resolutionof multicriteria, multienvironment and multiactor problems in which subjective aspectsand uncertainty have been incorporated into the model, constructing ratio scales correspondingto the priorities relative to the elements being compared, normalised in adistributive manner (wi = 1). On the basis of the individuals’ priorities we identifydifferent clusters for the decision makers and, for each of these, the associated preferencestructure using, to that end, tools analogous to those of Multidimensional Scaling.The resulting PS will be employed to extract knowledge for the subsequent negotiationprocesses and, should it be necessary, to determine the relative importance of thealternatives being compared using anyone of the existing procedures

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Työssä tehtiin ydinvoimalaitoksen suunnitellun alas- ja ylösajon todennäköisyysperus-tainen riskianalyysi. Suunnitellun alasajon analyysi sisälsi Teollisuuden Voima Oyj:n käyttämän vanhan PRA-mallin päivityksen ja laajentamisen. Ylösajon analyysiä varten kehitettiin kokonaan uusi malli. Diplomityöselostuksen alussa on yleinen katsaus luotettavuustekniikan käsitteisiin, pe-rusperiaatteisiin ja työkaluihin. Sitten on esitelty laitostekniikkaa tärkeimpien alas- ja ylösajoihin osallistuvien järjestelmien osalta. Myös normaalit alas- ja ylösajotoimenpi-teet on kuvattu. Yleisen teoriaosuuden jälkeen on keskitytty uusien mallien muodosta-miseen. Työssä käytetyt oletukset ja arviot on esitelty perusteluineen. Uudet tapahtuma- ja vikapuut sekä niiden perusteella lasketut sydänvaurioriskit johtopäätöksineen on käy-ty läpi selostuksen lopussa. Alkutapahtumataajuuksien määrittäminen tehtiin vikapuiden avulla, joissa huomioitiin komponenttivikojen, inhimillisten virheiden ja ulkoisten tekijöiden vaikutus. Aiemmin alkutapahtumat oli määritetty pääasiassa käyttöhistorian perusteella. Uusi määrittelytapa antaa eri vikaantumistapojen välille paremman kuvan niiden keskinäisestä merkitykses-tä sekä paremman päivitettävyyden laitosmuutosten yhteydessä. Mallien avulla voidaan laskea alas- ja ylösajon merkitys kokonaissydänvauriotaajuuteen entistä yksityiskohtaisemmin. Tuloksia voidaan myös hyödyntää laitosten vikatilanteis-sa, kun vertaillaan jatketun käytön ja mahdollisten korjaustöiden vaatiman alas- ja ylösajon riskejä. Uusien mallien antamat tulokset laskivat vain hieman kokonaissydän-vauriotaajuutta, mutta merkittävästi alasajon vaikutusta siihen. Ylösajosta aiheutuva riskinlisä oli noin puolet alasajon riskistä.

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A method to detect Apple stem grooving virus (ASGV) based on reverse transcription polymerase chain reaction (RT-PCR) was developed using primers ASGV4F-ASGV4R targeting the viral replicase gene, followed by a sandwich hybridisation, in microtiter plates, for colorimetric detection of the PCR products. The RT-PCR was performed with the Titan™ RT-PCR system, using AMV and diluted crude extracts of apple (Malus domestica) leaf or bark for the first strand synthesis and a mixture of Taq and PWO DNA polymerase for the PCR step. The RT-PCR products is hybridised with both a biotin-labelled capture probe linked to a streptavidin-coated microtiter plate and a digoxigenin (DIG)-labelled detection probe. The complex was detected with an anti-DIG conjugate labelled with alkaline phosphatase. When purified ASGV was added to extracts of plant tissue, as little as 400 fg of the virus was detected with this method. The assay with ASGV4F-ASGV4R primers specifically detected the virus in ASGV-infected apple trees from different origins, whereas no signal was observed with amplification products obtained with primers targeting the coat protein region of the ASGV genome or with primers specific for Apple chlorotic leaf spot virus (ACLSV) and Apple stem pitting virus (ASPV). The technique combines the power of PCR to increase the number of copies of the targeted gene, the specificity of DNA hybridization, and the ease of colorimetric detection and sample handling in microplates.

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The influence of medical students' knowledge concerning end-of-life care, considering ethical theories and clinical practice, remains controversial. We aimed to investigate medical students' knowledge of bioethical concepts related to moral kinds of death (euthanasia, disthanasia, and orthothanasia) and to analyze the influence of their clinical experience on practicing such approaches in a tertiary hospital in the state of São Paulo, Brazil. We interviewed 180 medical students [distributed in Group 1 (G1) - first to third- year students, and Group 2 (G2) - fourth to sixth-year students] to evaluate the influence of the course on "medical ethics" on ethical theories and clinical practice, using a closed questionnaire. The course on "medical ethics" did not distinguish the groups (P=0.704) in relation to bioethical concepts. Neologisms such as "cacothanasia" and "idiothanasia" were incorrectly viewed as bioethical concepts by 28% of the interviewees. Moreover, 45.3% of the sample considered health care professionals incapable of managing terminally ill patients, especially G2 (29%) as compared to G1 (16.5%, P=0.031). The concept of euthanasia was accepted by 41% of sample, as compared to 98.2% for orthothanasia. Among medical students that accepted ways to abbreviate life (22.9%), 30.1% belonged to G1, and only 16.1% to G2 (P=0.049). These medical students were unfamiliar with common bioethical concepts. Moreover, they considered healthcare professionals incapable of managing terminally ill patients. The ethical ideal of the "good death" reflects better acceptance of orthothanasia by medical students, suggesting a tendency to apply it in their future clinical practice.

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The aim of the study was to examine foreign operation methods and suggest the entry mode for the Russian E-business market. Ampparit Inc. was chosen as a case company, as it operates in the e-commerce B2B type of the business by providing Witpik - media monitoring service. The concept of foreign operation method was clarified with a specific focus on Russian market peculiarities and E-business. The main focuses of the present work were to figure out the most applicable entry mode for the Russian market in case of e-business company and factors affecting the decision about entry, including risks, barriers and other aspects.

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Solar radiation is an important factor for plant growth, being its availability to understory crops strongly modified by trees in an Agroforestry System (AFS). Coffee trees (Coffea arabica - cv. Obatã IAC 1669-20) were planted at a 3.4 x 0.9 m spacing inside and aside rows of monocrops of 12 year-old rubber trees (Hevea spp.), in Piracicaba-SP, Brazil (22º42'30" S, 47º38'00" W - altitude: 546m). One-year-old coffee plants exposed to 25; 30; 35; 40; 45; 80; 90; 95 and 100% of the total solar radiation were evaluated according to its biophysical parameters of solar radiation interception and capture. The Goudriaan (1977) adapted by Bernardes et al. (1998) model for radiation attenuation fit well to the measured data. Coffee plants tolerate a decrease in solar radiation availability to 50% without undergoing a reduction on growth and LAI, which was approximately 2m².m-2 under this condition. Further reductions on the availability of solar radiation caused a reduction in LAI (1.5m².m-2), thus poor land cover and solar radiation interception, resulting in growth reduction.

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Water uptake and use by plants are essentially energy processes that can be largely modified by percentage of soil cover, plant type; foliage area and its distribution; phenological stage and several environmental factors. Coffee trees (Coffea arabica - cv. Obatã IAC 1669-20) in Agrforestry System (AFS) spaced 3.4x0.9m apart, were planted inside and along rows of 12- year-old rubber trees (Hevea spp.) in Piracicaba-SP, Brazil (22 42'30" S, 47 38'00" W - altitude: 546m). Sap flow of one-year-old coffee plants exposed to 35; 45; 80; 95 and 100% of total solar radiation was estimated by the heat balance technique (Dynamax Inc.). Coffee plants under shade showed greater water loss per unit of incident irradiance. On the other hand, plants in monocrop (full sun) had the least water loss per unit of incident irradiance. For the evaluated positions average water use was (gH2O.m-2Leaf area.MJ-1): 64.71; 67.75; 25.89; 33.54; 27.11 in Dec./2002 and 97.14; 72.50; 40.70; 32.78; 26.13 in Feb./2003. This fact may be attributed to the higher stomata sensitivity of the coffee plants under more illuminated conditions, thus plants under full sun presented the highest water use efficiency. Express transpiration by leaf mass can be a means to access plant adaptation to the various environments, which is inaccessible when the approach is made by leaf area.

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This work was done at a gold mine company in Paracatu, MG, Brazil, and was conducted from March 2000 to November 2005. The substrate (spoil) studied was a phillite rock which contains sulfides such as pyrite and arsenopyrite. This study aimed to evaluate the survival and growth of plant species on different combinations of substrate layers over the spoil. These layers were a cover layer and a sealing layer, both deposited over the spoil. The treatment 1 had saprolite (B1) in the sealing layer (SL) and B1 with liming (B1L) in the cover layer (CL). The treatment 2 had B1 in SL and B1L + soil with liming (SoL) in the CL. The treatment 3 had B1 + SoL in the SL and B1L in the CL. The treatment 4 had B1 + SoL in the SL and B1L + SoL in the CL. The plant species used were Acacia farnesiana, A. holosericea, A. polyphylla, Albizia lebbeck, Clitoria fairchildiana, Flemingia sp., Mimosa artemisiana, M. bimucronata e Enterolobium contortisiliquum. Forty and 57 months after planting, collardiameter, height, and living plants were evaluated. The greatest survival rate was oobservedintreatmentwith B horizon of an Oxisoil in both layers, with 80 %. In general, M. bimucronata and A. farnesiana species showed the highest survival rate. The arsenic-content by Mehlich 3 in the cover layer ranged from 0.00 to 14.69 mg dm- 3 among treatments. The experimental results suggest that layers combinations above the sulfide substrate allow the rapid revegetation of the spoil.

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Bauhinia variegata and B. variegata var. candida, commonly known as orchid trees, are small sized trees widely used for urban forestry and landscaping. Adult plants grow under full sun; in Brazil, however, seedlings are generally cultivated in commercial nurseries under natural half-shading. The objective of this study was to evaluate the influence of different colored shade nets and light conditions on the initial growth of B. variegata and B. variegata var. candida. The influence of six light conditions (red net with 50% shading; blue net with 50% shading; black net with 70% shading; black net with 50% shading; black net with 30% shading; and full sun) on the initial growth of B. variegata and B. variegata var. candida were evaluated along 160 days, and growth relationships were calculated. Seedlings showed more efficiency on the use of photoassimilated compounds when grown under full sun. Such condition is the most appropriate for seedling production of B. variegata and B. variegata var. candida, contradicting what has been performed in practice.

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Eucalyptus plantations represent a short term and cost efficient alternative for sequestrating carbon dioxide from the atmosphere. Despite the known potential of forest plantations of fast growing species to store carbon in the biomass, there are relatively few studies including precise estimates of the amount of carbon in these plantations. In this study it was determined the carbon content in the stems, branches, leaves and roots of a clonal Eucalyptus grandis plantation in the Southeast of Brazil. We developed allometric equations to estimate the total amount of carbon and total biomass, and produced an estimate of the carbon stock in the stand level. Altogether, 23 sample trees were selected for aboveground biomass assessment. The roots of 9 of the 23 sampled trees were partially excavated to assess the belowground biomass at a singletree level. Two models with DBH, H and DBH2H were tested. The average relative share of carbon content in the stem, branch, leaf and root compartments was 44.6%, 43.0%, 46.1% and 37.8%, respectively, which is smaller than the generic value commonly used (50%). The best-fit allometric equations to estimate the total amount of carbon and total biomass had DBH2H as independent variable. The root-to-shoot ratio was relatively stable (C.V. = 27.5%) probably because the sub-sample was composed of clones. Total stand carbon stock in the Eucalyptus plantation was estimated to be 73.38 MgC ha-1, which is within the carbon stock range for Eucalyptus plantations.

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ABSTRACTWhile a number of papers have shown that subway systems have an impact on the air quality through the release of particulate matters, no information about the impact of such particles on tree attributes is available. Tree leaves from three different species from the exit side of a subway station in Rio de Janeiro, Brazil, were more asymmetrical than leaves from the entrance side. This leaves also presenting changes in leaves cuticle and chlorophyll content.