894 resultados para ADAMS-TYPE CYCLIC METHODS


Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this paper we determine a matrix S and a vector l for stiffly-stable Adams-type cyclic methods that are insensitive to step size changes by using the definition of equivalent methods, (see, e.g. [l]), in the Nordsieck notation. The elements S and l, written in a parametric form, permit us to represent in Nordsieck form the methods that were constructed in [7] and the new methods that satisfy the above properties.

Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective: To report on the presence of current and lifetime eating disorders (ED) in a well-defined sample of 137 female individuals with bipolar disorder type I. Methods: Trained psychiatrists interviewed the patients, and the diagnoses of BD and comorbidities were confirmed using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Axis I Disorders. Clinical and demographic characteristics of both groups (group with ED vs. group without ED) were compared. Results: Female patients with ED had an earlier onset of BD and an increased number of mood episodes, predominantly depressive. Women in the ED group also had higher rates of comorbidity with substance use disorders and anxiety disorders and reported a history of suicide attempts more frequently than women without ED. Conclusion: The presence of ED is a correlate of severity of BD type 1, and interventions should be developed to minimize distress and suicide risk and to improve treatment outcome. (C) 2010 Elsevier B.V. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective: To compare the variability of patterns of depressive symptoms between two consecutive depressive episodes in patients with bipolar disorder type I. Methods: Review of prospectively collected data from 136 subjects of an out-patient bipolar unit from 1997 to 2007. Binomial statistics was used for the analysis of Hamilton Depression Rating Scale (HDRS)-31 items of the first and second episodes, and the correlation of the HDRS-31 item scores of both episodes was determined using the Spearman coefficient. Results: Ten depressive symptoms showed a significant correlation between index and subsequent episodes: psychological anxiety, somatic anxiety, somatic symptoms, diurnal variation, paranoid symptoms, obsessive and compulsive symptoms, hypersomnia, loss of appetite and helplessness. Only four symptoms were stable in both statistical tests: paranoid symptoms, obsessive-compulsive symptoms, loss of appetite and hypersomnia. Conclusions: Paranoid and obsessive-compulsive symptoms, loss of appetite and hypersomnia tended to be found in successive episodes. However, the moderate correlations of the symptoms across two depressive recurrences suggested that clinical presentations in bipolar depression may not be predicted by symptom profiles presented in previous episodes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Energy efficiency is an important topic when considering electric motor drives market. Although more efficient electric motor types are available, the induction motor remains as the most common industrial motor type. IEC methods for determining losses and efficiency of converter-fed induction motors were introduced recently with the release of technical specification IEC/TS 60034-2-3. Determining the induction motor losses with IEC/TS 60034-2-3 method 2-3-A and assessing the practical applicability of the method are the main interests of this study. The method 2-3-A introduces a specific test converter waveform to be used in the measurements. Differences between the induction motor losses with a test converter supply, and with a DTC converter supply are investigated. In the IEC methods, the tests are run at motor rated fundamental voltage, which, in practice, requires the frequency converter to be fed with a risen input voltage. In this study, the tests are run on both frequency converters with artificially risen converter input voltage, resulting in rated motor fundamental input voltage as required by IEC. For comparison, the tests are run with both converters on normal grid input voltage supply, which results in lower motor fundamental voltage and reduced flux level, but should be more relevant from practical point of view. According to IEC method 2-3-A, tests are run at rated motor load, and to ensure comparability of the results, the rated load is used in the grid-fed converter measurements, although motor is overloaded while producing the rated torque at reduced flux level. The IEC 2-3-A method requires also sinusoidal supply test results with IEC method 2-1-1B. Therefore, the induction motor losses with the recently updated IEC 60034-2-1 method 2-1-1B are determined at the motor rated voltage, but also at two lower motor voltages, which are according to the output fundamental voltages of the two network-supplied converters. The method 2-3-A was found to be complex to apply but the results were stable. According to the results, the method 2-3-A and the test converter supply are usable for comparing losses and efficiency of different induction motors at the operating point of rated voltage, rated frequency and rated load, but the measurements do not give any prediction of the motor losses at final application. One might therefore strongly criticize the method’s main principles. It seems, that the release of IEC 60034-2-3 as a technical specification instead of a final standard for now was justified, since the practical relevance of the main method is questionable.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

L'utilisation des méthodes formelles est de plus en plus courante dans le développement logiciel, et les systèmes de types sont la méthode formelle qui a le plus de succès. L'avancement des méthodes formelles présente de nouveaux défis, ainsi que de nouvelles opportunités. L'un des défis est d'assurer qu'un compilateur préserve la sémantique des programmes, de sorte que les propriétés que l'on garantit à propos de son code source s'appliquent également au code exécutable. Cette thèse présente un compilateur qui traduit un langage fonctionnel d'ordre supérieur avec polymorphisme vers un langage assembleur typé, dont la propriété principale est que la préservation des types est vérifiée de manière automatisée, à l'aide d'annotations de types sur le code du compilateur. Notre compilateur implante les transformations de code essentielles pour un langage fonctionnel d'ordre supérieur, nommément une conversion CPS, une conversion des fermetures et une génération de code. Nous présentons les détails des représentation fortement typées des langages intermédiaires, et les contraintes qu'elles imposent sur l'implantation des transformations de code. Notre objectif est de garantir la préservation des types avec un minimum d'annotations, et sans compromettre les qualités générales de modularité et de lisibilité du code du compilateur. Cet objectif est atteint en grande partie dans le traitement des fonctionnalités de base du langage (les «types simples»), contrairement au traitement du polymorphisme qui demande encore un travail substantiel pour satisfaire la vérification de type.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

[EN] We analyze the discontinuity preserving problem in TV-L1 optical flow methods. This type of methods typically creates rounded effects at flow boundaries, which usually do not coincide with object contours. A simple strategy to overcome this problem consists in inhibiting the diffusion at high image gradients. In this work, we first introduce a general framework for TV regularizers in optical flow and relate it with some standard approaches. Our survey takes into account several methods that use decreasing functions for mitigating the diffusion at image contours. Consequently, this kind of strategies may produce instabilities in the estimation of the optical flows. Hence, we study the problem of instabilities and show that it actually arises from an ill-posed formulation. From this study, it is possible to come across with different schemes to solve this problem. One of these consists in separating the pure TV process from the mitigating strategy. This has been used in another work and we demonstrate here that it has a good performance. Furthermore, we propose two alternatives to avoid the instability problems: (i) we study a fully automatic approach that solves the problem based on the information of the whole image; (ii) we derive a semi-automatic approach that takes into account the image gradients in a close neighborhood adapting the parameter in each position. In the experimental results, we present a detailed study and comparison between the different alternatives. These methods provide very good results, especially for sequences with a few dominant gradients. Additionally, a surprising effect of these approaches is that they can cope with occlusions. This can be easily achieved by using strong regularizations and high penalizations at image contours.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

BACKGROUND Type D personality (Type D) is an independent psychosocial risk factor for poor cardiac prognosis and increased mortality in patients with cardiovascular disease (CVD), but the involved mechanisms are poorly understood. Macrophages play a pivotal role in atherosclerosis, the process underlying coronary artery disease (CAD). We investigated macrophage superoxide anion production in production in CAD patients with and without Type D. METHODS AND RESULTS We studied 20 male CAD patients with Type D (M:66.7±9.9years) and 20 age-matched male CAD patients without Type D (M:67.7±8.5years). Type D was measured using the DS14 questionnaire with the two subscales 'negative affectivity' and 'social inhibition'. We assessed macrophage superoxide anion production using the WST-1 assay. All analyses were controlled for potential confounders. CAD patients with Type D showed higher superoxide anion production compared to CAD patients without Type D (F(1,38)=15.57, p<0.001). Complementary analyses using the Type D subscales 'negative affectivity' and 'social inhibition', and their interaction as continuous measures, showed that both Type D subscales (negative affectivity: (ß=0.48, p=0.002, R(2)=0.227); social inhibition: (ß=0.46, p=0.003, R(2)=0.208)) and their interaction (ß=0.36, p=0.022, R(2)=0.130) were associated with higher WST-1 reduction scores. Results remained significant when controlling for classical CVD risk factors (i.e. body mass index, mean arterial blood pressure), atherosclerosis severity (i.e. intima media thickness, presence of carotid plaques), and psychological factors (depressive symptom severity, chronic stress). CONCLUSIONS Our results indicate higher macrophage superoxide anion production in CAD patients with Type D compared to those without Type D. This may suggest a mechanism contributing to increased morbidity and mortality in CAD patients with Type D.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The cyclic β-(1→3),β-(1→6)-d-glucan synthesis locus of Bradyrhizobium japonicum is composed of at least two genes, ndvB and ndvC. Mutation in either gene affects glucan synthesis, as well as the ability of the bacterium to establish a successful symbiotic interaction with the legume host soybean (Glycine max). B. japonicum strain AB-14 (ndvB::Tn5) does not synthesize β-glucans, and strain AB-1 (ndvC::Tn5) synthesizes a cyclic β-glucan lacking β-(1→6)-glycosidic bonds. We determined that the structure of the glucan synthesized by strain AB-1 is cyclodecakis-(1→3)-β-d-glucosyl, a cyclic β-(1→3)-linked decasaccharide in which one of the residues is substituted in the 6 position with β-laminaribiose. Cyclodecakis-(1→3)-β-d-glucosyl did not suppress the fungal β-glucan-induced plant defense response in soybean cotyledons and had much lower affinity for the putative membrane receptor protein than cyclic β-(1→3),β-(1→6)-glucans produced by wild-type B. japonicum. This is consistent with the hypothesis presented previously that the wild-type cyclic β-glucans may function as suppressors of a host defense response.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Composition methods are useful when solving Ordinary Differential Equations (ODEs) as they increase the order of accuracy of a given basic numerical integration scheme. We will focus on sy-mmetric composition methods involving some basic second order symmetric integrator with different step sizes [17]. The introduction of symmetries into these methods simplifies the order conditions and reduces the number of unknowns. Several authors have worked in the search of the coefficients of these type of methods: the best method of order 8 has 17 stages [24], methods of order 8 and 15 stages were given in [29, 39, 40], 10-order methods of 31, 33 and 35 stages have been also found [24, 34]. In this work some techniques that we have built to obtain 10-order symmetric composition methods of symmetric integrators of s = 31 stages (16 order conditions) are explored. Given some starting coefficients that satisfy the simplest five order conditions, the process followed to obtain the coefficients that satisfy the sixteen order conditions is provided.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Brazilian propolis type 6 (Atlantic forest, Bahia) is distinct from the other types of propolis especially due to absence of flavonoids and presence of other non-polar, long chain compounds, but presenting good in vitro and in vivo antimicrobial activity. Several authors have suggested that fatty acids found in this propolis might be responsible for its antimicrobial activity; however, so far no evidence concerning this finding has been reported in the literature. The goals of this study were to evaluate the antibacterial activity of the main pure fatty acids in the ethanolic extract and fractions and elucidate the chemical nature of the bioactive compounds isolated from Brazilian propolis type 6. Methods: Brazilian propolis type 6 ethanolic extract (EEP), hexane fraction (H-Fr), major fatty acids, and isolated sub-fractions were analyzed using high performance liquid chromatography (HPLC), high resolution gas chromatography with flame ionization detection (HRGC-FID), and gas chromatography-mass spectrometry (GC-MS). Three sub-fractions of H-Fr were obtained through preparative HPLC. Antimicrobial activity of EEP, H-Fr, sub-fractions, and fatty acids were tested against Staphyloccus aureus ATCC 25923 and Streptococcus mutans Ingbritt 1600 using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results: EEP and H-Fr inhibited the growth of the microorganisms tested; nevertheless, no antimicrobial activity was found for the major fatty acids. The three sub-fractions (1, 2, and 3) were isolated from H-Fr by preparative HPLC and only sub-fraction 1 showed antimicrobial activity. Conclusion: a) The major fatty acids tested were not responsible for the antimicrobial activity of propolis type 6; b) Sub-fraction 1, belonging to the benzophenone class, was responsible for the antimicrobial activity observed in the present study. The identification of the bioactive compound will improve the development of more efficient uses of this natural product.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Heterozygotes for the C282Y mutation of the HFE gene may have altered hematology indices and higher iron stores than wild-type subjects. Methods: We performed a cross-sectional analysis of 1488 females and 1522 males 20-79 years of age drawn from the Busselton (Australia) population study to assess the effects of HFE genotype, age, gender, and lifestyle on serum iron and hematology indices. Results: Male C282Y heterozygotes had increased transferrin saturation compared with the wild-type genotype. Neither male nor female heterozygotes had significantly increased ferritin values compared with the wild-type genotype. Younger (20-29 years) wild-type males, but not heterozygous males, had significantly lower ferritin values than wild-type males in the older age groups. Compound heterozygous subjects had increased means for serum iron, transferrin saturation, corpuscular volume, and corpuscular hemoglobin compared with the wild-type genotype, and the males also had increased ferritin values (medians 323 vs 177 mug/L; P = 0.003). In both male and female wild-type subjects, an increased body mass index was associated with decreased serum iron and transferrin saturation and increased ferritin values. There was a significant increase in ferritin concentrations in both genders with increasing frequency of red meat consumption above a baseline of 1-2 times per week and alcohol intakes >10 g/day. Conclusions: Male C282Y heterozygotes had significantly increased transferrin saturation values. Compound heterozygous (C282Y/H63D) subjects formed a separate category of C282Y heterozygotes in whom both iron and red cell indices were significantly increased compared with the wild-type genotype. (C) 2001 American Association for Clinical Chemistry.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Apesar da enorme evolução tecnológica, os prazos na construção são cada vez mais reduzidos e os custos mais controlados, verificando-se uma despreocupação no que diz respeito a aspetos como a qualidade e durabilidade da construção das estruturas. Desperta assim nos técnicos, donos-de-obra, entidades executantes e projetistas a necessidade de avaliar o estado de conservação das estruturas de betão armado. Esta dissertação tem como objetivo principal abordar as anomalias e os mecanismos de deterioração mais correntes, os métodos de ensaio destrutivos ou parcialmente destrutivos mais utilizados e adequados, e abordar algumas das técnicas de reparação e reforço das estruturas de betão armado. Os principais danos apresentados nas estruturas são devidos a agentes físicos, mecânicos, biológicos e químicos. Podem ser devidos a causas diretas (acidentais ou naturais), que acarretam uma ação concreta sobre os elementos estruturais, e causas indiretas (humanas), diretamente ligadas com erros de projeto. É primordial fazer-se o levantamento de todas as anomalias existentes para se recorrer a um método de inspeção e ensaio. Consoante a necessidade de informação e estado da estrutura são selecionados os ensaios a realizar, podendo ser realizados “in situ” ou em laboratório. As técnicas de reparação e reforço são vistas como métodos para melhorar as condições da estrutura ao nível da segurança, desempenho, habitabilidade e durabilidade, prevenindo a evolução dos mecanismos de deterioração.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Proposit: L'objectiu d'aquest treball és analitzar quins efectes produeix un programa d'activitat física en pacients amb trastorn bipolar de tipus II. Mètodes: Per la realització d'aquest estudi he comptat amb una mostra petita (n=14), la qual estava dividida en grup control (n=7) i grup intervenció (n=7). Es va realitzar una valoració inicial de la mostra per mitjà del Yesavage i SF-12. Posteriorment el grup intervenció va participar en 20 sessions d'activitat física (freq: 2/set). Un cop finalitzat el programa es va tornar a valorar la mostra per mitjà del Yesavage i SF-12. Resultats: Els subjectes del grup intervenció van millorar en: Estat d'ànim (Yesavage), Percepció de la pròpia salut, nivell d'energia i sentiment de tristesa i desànim. En l'estat de tranquil·litat i calma no van mostrar una gran variació. Conclusions: La pràctica d'activitat física en grup millora l'estat d'ànim, percepció de pròpia salut, redueix l'estat de tristesa i desànim i nivell d'energia.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tämän diplomityön tavoitteena oli saada perustietoa tekijöistä, jotka vaikuttavat musteen kuivumiseen erilaisilla paperipinnoilla inkjet tulostuksessa. Tavoitteena oli saada tietoa erilaisista musteista, joita käytetään yleisimmissä inkjet tulostustekniikoissa, miten paperit vaikuttavat musteen kuivumiseen ja minkälaisia menetelmiä on olemassa musteen kuivumistekijöiden määrittämiseen. Lisäksi tarkoituksena oli varmistaa, voidaanko inkjetmusteiden absorptioajan määrittämiseen käytettävää DIGAT-laitetta käyttää määrittämään ja ennustamaan erilaisten musteiden kuivumista erilaisilla paperipinnoilla sekä etsiä korrelaatioita musteen absorptioajan ja teknisten paperiominaisuuksien sekä inkjet tulostuksen laadun välillä. Kirjallisuusosassa tarkasteltiin erilaisia inkjet tulostusmenetelmiä, niissä käytettäviä musteita ja musteiden koostumuksia. Tutkittiin myös paperin ja musteen välisiä vuorovaikutuksia sekä inkjet tulostuksen laatua. Kokeellisessa osassa tutkittiin musteenabsorboitumista paperiin DIGAT-laitteen avulla. kuudella eri musteella. Paperinäytteistä määritettiin teknisiä paperiominaisuuksia sekä ominaisuuksia, jotka liittyvät inkjet tulostuksen laatuun. Inkjet tulostuksen laatua tarkasteltiin tulostamalla testikuva kolmella eri tulostimella, jotka olivat Canon Bubble Jet i950, HP DeskJet Cxi970 ja Epson Stylus C46. Havaittiin, että DIGAT-laite ei sovellu määrittämään musteen absorptioaikoja kiiltäville näytteille.Tässä tutkimuksessa näyte, jonka kiilto oli 65 %, oli liian kiiltävä mitattavaksi DIGAT-laitteella. Lisäksi absorptiomäärityksissä havaittiin, että erilaiset musteet asettuvat erilailla paperin pintaan ja että pigmenttipohjaisella musteella asettumisaika oli kaikista pisin. Musteiden absorptioajat olivat nopeimpia erikoisinkjetpaperilla ja hitaimpia päällystetyillä, tiiviillä papereilla. Musteen absorptioajan ja teknisten paperiominaisuuksien ja inkjet tulostuksen laadun välisiä korrelaatioita oli vaikea havaita. Voidaan sanoa, että tulokset olivat muste- ja printterikohtaisia. Havaittiin vain muutamia teknisiä paperiominaisuuksia, jotka korreloivat hyvin musteen absorboitumisen kanssa. Nämäolivat Gurley-Hill huokoisuus, paperin tuhka- sekä kalsiumkarbonaattipitoisuus ja K&N värinabsorptio. Myöskään inkjet tulostuksen laadun ja musteen absorption välisiä korrelaatioita ei löytynyt kuin muutama; densiteetti, mottling sekä bleeding. Tämän tutkimuksen perusteella voidaan todeta DIGAT-laitteen soveltuvan hyvin kuvaamaan inkjet tulostuksen laatuominaisuuksista densiteettia, mottlingia sekä bleedingiä. DIGAT-laitetta voidaan siis käyttää avuksi ennustettaessa kuivumisaikaa ja sen vaikutusta edellä mainittuihin ominaisuuksiin. Läpipainatusominaisuuksia DIGAT-laitteen avulla ei voida tutkia, sillä ne ovat enemmän riippuvaisia paperin neliömassasta, paksuudesta ja huokoisuudesta kuinmusteen absorptioajasta. Teknisistä paperiominaisuuksista Gurley-Hill huokoisuus, paperin tuhka-sekä CaCO3-pitoisuus ja K&N värinabsorptio kuvaavat hyvin musteen imeytymisaikaa paperiin, kun taas ominaisuudet Cobb, HST ja polaari- sekädispersiokomponentit eivät kuvaa. Näyttää siltä, että testikuva, joka on tällä hetkellä käytössä UPM Tutkimus-keskuksessa, ei sovellu suurtehotulostuksen laadun tarkkailuun. Testikuva toimii hyvin pöytätulostimilla ja perinteisillä kopiopapereilla ja inkjetpapereilla, jotka on tarkoitettu tulostettaviksi hitaasti. Tulostusnopeuden ja musteen kuivumisnopeuden välisiä ilmiöitä seei tuo esille, joten se ei sovellu kuvaamaan suurtehotulostusta.