986 resultados para Starting materials


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The major objective of this project is to evaluate image analysis for characterizing air voids in Portland cement contract (PCC) and asphalt concrete (AC) and aggregate gradation in asphalt concrete. Phase 1 of this project has concentrated on evaluation and refinement of sample preparation techniques, evaluation of methods and instruments for conducting image analysis, and finally, analysis and comparison of a select portion of samples. Preliminary results suggest a strong correlation between the results obtained from the linear traverse method and image analysis methods for determining percent air voids in concrete. Preliminary work with asphalt samples has shown that damage caused by a high vacuum of the conventional scanning electron microscope (SEM) may too disruptive. Alternative solutions have been explored, including confocal microscopy and low vacuum electron microscopy. Additionally, a conventional high vacuum SEM operating at a marginal operating vacuum may suffice.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The coefficients of relative strength (CORS) of base courses for use in the American association state highway officials (AASHO) interim guide for the design of flexible pavements are determined here. Based on (1) volumetric strain--axial strain relationships at minimum volume, and (2) effective stress ratio-cohesion relationships at maximum effective stress ratio, CORS were determined from the results of laboratory triaxial tests on both asphalt-treated and untreated aggregate base course materials. The researchers conclude that volumetric strain-axial strain at minimum volume appear to be appropriate parameters for determining CORS.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This bulletin is a compilation of the reports on completed research done for the Iowa State Highway Research Board Project HR-1, "The Loess and Glacial Till Materials of Iowa; an Investigation of Their Physical and Chemical Properties and Techniques for Processing Them to Increase Their All-Weather Stability for Road Construction.” The research, started in 1950, was done by the Iowa Engineering Experiment Station under its project 283-S. The project was supported by funds from the Iowa State Highway Commission.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose This study seeks to analyse the policies of library and information science (LIS) journals regarding the publication of supplementary materials, the number of journals and articles that include this feature, the kind of supplementary materials published with regard to their function in the article, the formats employed and the access provided to readers. Design/methodology/approach The study analysed the instructions for authors of LIS journals indexed in the ISI Journal Citation Reports, as well as the supplementary materials attached to the articles published in their 2011 online volumes. Findings Large publishers are more likely to have a policy regarding the publication of supplementary materials, and policies are usually homogeneous across all the journals of a given publisher. Most policies state the acceptance of supplementary materials, and even journals without a policy also publish supplementary materials. The majority of supplementary materials provided in LIS articles are extended methodological explanations and additional results in the form of textual information in PDF or Word files. Some toll-access journals provide open access to any reader to these files. Originality/value This study provides new insights into the characteristics of supplementary materials in LIS journals. The results may be used by journal publishers to establish a policy on the publication of supplementary materials and, more broadly, to develop data sharing initiatives in academic settings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Les plantes sont essentielles pour les sociétés humaines. Notre alimentation quotidienne, les matériaux de constructions et les sources énergétiques dérivent de la biomasse végétale. En revanche, la compréhension des multiples aspects développementaux des plantes est encore peu exploitée et représente un sujet de recherche majeur pour la science. L'émergence des technologies à haut débit pour le séquençage de génome à grande échelle ou l'imagerie de haute résolution permet à présent de produire des quantités énormes d'information. L'analyse informatique est une façon d'intégrer ces données et de réduire la complexité apparente vers une échelle d'abstraction appropriée, dont la finalité est de fournir des perspectives de recherches ciblées. Ceci représente la raison première de cette thèse. En d'autres termes, nous appliquons des méthodes descriptives et prédictives combinées à des simulations numériques afin d'apporter des solutions originales à des problèmes relatifs à la morphogénèse à l'échelle de la cellule et de l'organe. Nous nous sommes fixés parmi les objectifs principaux de cette thèse d'élucider de quelle manière l'interaction croisée des phytohormones auxine et brassinosteroïdes (BRs) détermine la croissance de la cellule dans la racine du méristème apical d'Arabidopsis thaliana, l'organisme modèle de référence pour les études moléculaires en plantes. Pour reconstruire le réseau de signalement cellulaire, nous avons extrait de la littérature les informations pertinentes concernant les relations entre les protéines impliquées dans la transduction des signaux hormonaux. Le réseau a ensuite été modélisé en utilisant un formalisme logique et qualitatif pour pallier l'absence de données quantitatives. Tout d'abord, Les résultats ont permis de confirmer que l'auxine et les BRs agissent en synergie pour contrôler la croissance de la cellule, puis, d'expliquer des observations phénotypiques paradoxales et au final, de mettre à jour une interaction clef entre deux protéines dans la maintenance du méristème de la racine. Une étude ultérieure chez la plante modèle Brachypodium dystachion (Brachypo- dium) a révélé l'ajustement du réseau d'interaction croisée entre auxine et éthylène par rapport à Arabidopsis. Chez ce dernier, interférer avec la biosynthèse de l'auxine mène à la formation d'une racine courte. Néanmoins, nous avons isolé chez Brachypodium un mutant hypomorphique dans la biosynthèse de l'auxine qui affiche une racine plus longue. Nous avons alors conduit une analyse morphométrique qui a confirmé que des cellules plus anisotropique (plus fines et longues) sont à l'origine de ce phénotype racinaire. Des analyses plus approfondies ont démontré que la différence phénotypique entre Brachypodium et Arabidopsis s'explique par une inversion de la fonction régulatrice dans la relation entre le réseau de signalisation par l'éthylène et la biosynthèse de l'auxine. L'analyse morphométrique utilisée dans l'étude précédente exploite le pipeline de traitement d'image de notre méthode d'histologie quantitative. Pendant la croissance secondaire, la symétrie bilatérale de l'hypocotyle est remplacée par une symétrie radiale et une organisation concentrique des tissus constitutifs. Ces tissus sont initialement composés d'une douzaine de cellules mais peuvent aisément atteindre des dizaines de milliers dans les derniers stades du développement. Cette échelle dépasse largement le seuil d'investigation par les moyens dits 'traditionnels' comme l'imagerie directe de tissus en profondeur. L'étude de ce système pendant cette phase de développement ne peut se faire qu'en réalisant des coupes fines de l'organe, ce qui empêche une compréhension des phénomènes cellulaires dynamiques sous-jacents. Nous y avons remédié en proposant une stratégie originale nommée, histologie quantitative. De fait, nous avons extrait l'information contenue dans des images de très haute résolution de sections transverses d'hypocotyles en utilisant un pipeline d'analyse et de segmentation d'image à grande échelle. Nous l'avons ensuite combiné avec un algorithme de reconnaissance automatique des cellules. Cet outil nous a permis de réaliser une description quantitative de la progression de la croissance secondaire révélant des schémas développementales non-apparents avec une inspection visuelle classique. La formation de pôle de phloèmes en structure répétée et espacée entre eux d'une longueur constante illustre les bénéfices de notre approche. Par ailleurs, l'exploitation approfondie de ces résultats a montré un changement de croissance anisotropique des cellules du cambium et du phloème qui semble en phase avec l'expansion du xylème. Combinant des outils génétiques et de la modélisation biomécanique, nous avons démontré que seule la croissance plus rapide des tissus internes peut produire une réorientation de l'axe de croissance anisotropique des tissus périphériques. Cette prédiction a été confirmée par le calcul du ratio des taux de croissance du xylème et du phloème au cours de développement secondaire ; des ratios élevés sont effectivement observés et concomitant à l'établissement progressif et tangentiel du cambium. Ces résultats suggèrent un mécanisme d'auto-organisation établi par un gradient de division méristématique qui génèrent une distribution de contraintes mécaniques. Ceci réoriente la croissance anisotropique des tissus périphériques pour supporter la croissance secondaire. - Plants are essential for human society, because our daily food, construction materials and sustainable energy are derived from plant biomass. Yet, despite this importance, the multiple developmental aspects of plants are still poorly understood and represent a major challenge for science. With the emergence of high throughput devices for genome sequencing and high-resolution imaging, data has never been so easy to collect, generating huge amounts of information. Computational analysis is one way to integrate those data and to decrease the apparent complexity towards an appropriate scale of abstraction with the aim to eventually provide new answers and direct further research perspectives. This is the motivation behind this thesis work, i.e. the application of descriptive and predictive analytics combined with computational modeling to answer problems that revolve around morphogenesis at the subcellular and organ scale. One of the goals of this thesis is to elucidate how the auxin-brassinosteroid phytohormone interaction determines the cell growth in the root apical meristem of Arabidopsis thaliana (Arabidopsis), the plant model of reference for molecular studies. The pertinent information about signaling protein relationships was obtained through the literature to reconstruct the entire hormonal crosstalk. Due to a lack of quantitative information, we employed a qualitative modeling formalism. This work permitted to confirm the synergistic effect of the hormonal crosstalk on cell elongation, to explain some of our paradoxical mutant phenotypes and to predict a novel interaction between the BREVIS RADIX (BRX) protein and the transcription factor MONOPTEROS (MP),which turned out to be critical for the maintenance of the root meristem. On the same subcellular scale, another study in the monocot model Brachypodium dystachion (Brachypodium) revealed an alternative wiring of auxin-ethylene crosstalk as compared to Arabidopsis. In the latter, increasing interference with auxin biosynthesis results in progressively shorter roots. By contrast, a hypomorphic Brachypodium mutant isolated in this study in an enzyme of the auxin biosynthesis pathway displayed a dramatically longer seminal root. Our morphometric analysis confirmed that more anisotropic cells (thinner and longer) are principally responsible for the mutant root phenotype. Further characterization pointed towards an inverted regulatory logic in the relation between ethylene signaling and auxin biosynthesis in Brachypodium as compared to Arabidopsis, which explains the phenotypic discrepancy. Finally, the morphometric analysis of hypocotyl secondary growth that we applied in this study was performed with the image-processing pipeline of our quantitative histology method. During its secondary growth, the hypocotyl reorganizes its primary bilateral symmetry to a radial symmetry of highly specialized tissues comprising several thousand cells, starting with a few dozens. However, such a scale only permits observations in thin cross-sections, severely hampering a comprehensive analysis of the morphodynamics involved. Our quantitative histology strategy overcomes this limitation. We acquired hypocotyl cross-sections from tiled high-resolution images and extracted their information content using custom high-throughput image processing and segmentation. Coupled with an automated cell type recognition algorithm, it allows precise quantitative characterization of vascular development and reveals developmental patterns that were not evident from visual inspection, for example the steady interspace distance of the phloem poles. Further analyses indicated a change in growth anisotropy of cambial and phloem cells, which appeared in phase with the expansion of xylem. Combining genetic tools and computational modeling, we showed that the reorientation of growth anisotropy axis of peripheral tissue layers only occurs when the growth rate of central tissue is higher than the peripheral one. This was confirmed by the calculation of the ratio of the growth rate xylem to phloem throughout secondary growth. High ratios are indeed observed and concomitant with the homogenization of cambium anisotropy. These results suggest a self-organization mechanism, promoted by a gradient of division in the cambium that generates a pattern of mechanical constraints. This, in turn, reorients the growth anisotropy of peripheral tissues to sustain the secondary growth.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work annealing and growth of CuInS2 thin films is investigated with quasireal-time in situ Raman spectroscopy. During the annealing a shift of the Raman A1 mode towards lower wave numbers with increasing temperature is observed. A linear temperature dependence of the phonon branch of ¿2 cm¿1/100 K is evaluated. The investigation of the growth process (sulfurization of metallic precursors) with high surface sensitivity reveals the occurrence of phases which are not detected with bulk sensitive methods. This allows a detailed insight in the formation of the CuInS2 phases. Independent from stoichiometry and doping of the starting precursors the CuAu ordering of CuInS2 initially forms as the dominating ordering. The transformation of the CuAu ordering into the chalcopyrite one is, in contrast, strongly dependent on the precursor composition and requires high temperatures.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this master's thesis was to analyse a competitive advantage of an Internet based marketing research company based on a competitive strategy oriented way. First Internet panel was compared to mostly used marketing research method, telephone interview. Secondly fourteen potential clients were interviewed personally. Intention was to find out what the potential clients thinkabout Zapera Finland Ltd and what kind of competitive strategy could be chosen considering costs, product differentiation, competition, research method, segmentation of business line and substitution. Finally the interviews were analysed and some strategic suggestions were made based on the competitive advatage(s). Conclusion was that Zapera Finland Ltd can choose a competitive strategy based on both the cost advantage and the product differentiation in a narrow competition scope.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Työssä tarkastellaan oppimisalustoilla käytettäviä testikysymyksiä ja oppisisältöjä uudelleen-käytettävyyden ja siirrettävyyden näkökulmasta. Tavoitteena on selvittää, minkälaisia välineitä määrämuotoisten sisältöjen tuottamista varten on olemassa, ja miten niillä luodut materiaalit ovat siirrettävissä työvälineestä toiseen ja oppimisalustoille. Tutkittavana ovat sisällön paketointiin tarkoitetutSCORM- ja IMS Content Packaging -spesifikaatiot sekä kysymysten esittämiseen tarkoitettu IMS Question and Test Interoperability -spesifikaatio. Pääpaino työssäon selvittää, miten oppisisällöt ovat siirrettävissä WebCT- ja Moodle-alustojenvälillä. Tähän liittyen on luotu ohjeistus, miten yksittäiset tiedostot, kysymykset ja Sisältökokonaisuus-työkalulla koostetut sisällöt siirretään WebCT:ltä Moodleen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

En aquest treball presentem una revisió del jaciment ibèric de la Serra de l’Espasa (Capçanes, Priorat) a partir de l’estudi, amb criteris actualitzats, del material conservat en el Museu Salvador Vilaseca de Reus. Els resultats són contrastats amb les darreres investigacions arqueològiques desenvolupades en el curs inferior de l’Ebre. A l’últim, s’analitzen les possibles interpretacions d’aquest conjunt, en particular la hipotètica existència d’un santuari, i les seves implicacions en el procés de romanització en aquesta zona.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ydinvoimalaitokset on suunniteltu ja rakennettu niin, että niillä on kyky selviytyä erilaisista käyttöhäiriöistä ja onnettomuuksista ilman laitoksen vahingoittumista sekä väestön ja ympäristön vaarantumista. On erittäin epätodennäköistä, että ydinvoimalaitosonnettomuus etenee reaktorisydämen vaurioitumiseen asti, minkä seurauksena sydänmateriaalien hapettuminen voi tuottaa vetyä. Jäädytyspiirin rikkoutumisen myötä vety saattaa kulkeutua ydinvoimalaitoksen suojarakennukseen, jossa se voi muodostaa palavan seoksen ilman hapen kanssa ja palaa tai jopa räjähtää. Vetypalosta aiheutuvat lämpötila- ja painekuormitukset vaarantavat suojarakennuksen eheyden ja suojarakennuksen sisällä olevien turvajärjestelmien toimivuuden, joten tehokas ja luotettava vedynhallintajärjestelmä on tarpeellinen. Passiivisia autokatalyyttisiä vetyrekombinaattoreita käytetäänyhä useammissa Euroopan ydinvoimaitoksissa vedynhallintaan. Nämä rekombinaattorit poistavat vetyä katalyyttisellä reaktiolla vedyn reagoidessa katalyytin pinnalla hapen kanssa muodostaen vesihöyryä. Rekombinaattorit ovat täysin passiivisiaeivätkä tarvitse ulkoista energiaa tai operaattoritoimintaa käynnistyäkseen taitoimiakseen. Rekombinaattoreiden käyttäytymisen tutkimisellatähdätään niiden toimivuuden selvittämiseen kaikissa mahdollisissa onnettomuustilanteissa, niiden suunnittelun optimoimiseen sekä niiden optimaalisen lukumäärän ja sijainnin määrittämiseen suojarakennuksessa. Suojarakennuksen mallintamiseen käytetään joko keskiarvoistavia ohjelmia (Lumped parameter (LP) code), moniulotteisia virtausmalliohjelmia (Computational Fluid Dynamics, CFD) tai näiden yhdistelmiä. Rekombinaattoreiden mallintaminen on toteutettu näissä ohjelmissa joko kokeellisella, teoreettisella tai yleisellä (eng. Global Approach) mallilla. Tämä diplomityö sisältää tulokset TONUS OD-ohjelman sisältämän Siemens FR90/1-150 rekombinaattorin mallin vedynkulutuksen tarkistuslaskuista ja TONUS OD-ohjelmalla suoritettujen laskujen tulokset Siemens rekombinaattoreiden vuorovaikutuksista. TONUS on CEA:n (Commissariat à 1'En¬ergie Atomique) kehittämä LP (OD) ja CFD -vetyanalyysiohjelma, jota käytetään vedyn jakautumisen, palamisenja detonaation mallintamiseen. TONUS:sta käytetään myös vedynpoiston mallintamiseen passiivisilla autokatalyyttisillä rekombinaattoreilla. Vedynkulutukseen vaikuttavat tekijät eroteltiin ja tutkittiin yksi kerrallaan. Rekombinaattoreiden vuorovaikutuksia tutkittaessa samaan tilavuuteen sijoitettiin eri kokoisia ja eri lukumäärä rekombinaattoreita. Siemens rekombinaattorimalli TONUS OD-ohjelmassa laskee vedynkulutuksen kuten oletettiin ja tulokset vahvistavat TONUS OD-ohjelman fysikaalisen laskennan luotettavuuden. Mahdollisia paikallisia jakautumia tutkitussa tilavuudessa ei voitu havaita LP-ohjelmalla, koska se käyttäälaskennassa suureiden tilavuuskeskiarvoja. Paikallisten jakautumien tutkintaan tarvitaan CFD -laskentaohjelma.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction: We report a case of digoxin intoxication with severe visual symptoms. Patients (or Materials) and Methods: Digoxin 0.25 mg QD for atrial fibrillation was prescribed to a 91-year-old woman with an estimated creatinine clearance of 18 mL/min. Within 2 to 3 weeks, she developed nausea, vomiting, and dysphagia, and began complaining of snowy and blurry vision, photopsia, dyschromatopsia, aggravated bedtime visual and proprioceptive illusions (she felt as being on a boat), and colored hallucinations. She consulted her family doctor twice and visited the eye clinic once until, 1 month after starting digoxin, impaired autonomy led her to be admitted to the emergency department. Results: Digoxin intoxication was confirmed by a high plasma level measured on admission (5.7 μg/L; reference range, 0.8-2 μg/L). After stopping digoxin, general symptoms resolved in a few days, but visual symptoms persisted. Ophtalmologic care and follow-up diagnosed digoxin intoxication superimposed on pre-existing left eye (LE) cataract, dry age-related macular degeneration (DMLA), and Charles Bonnet syndrome. Visual acuity was 0.4 (right eye, RE) and 0.5 (LE). Ocular fundus was physiologic except for bilateral dry DMLA. Dyschromatopsia was confirmed by poor results on Ishihara test (1/13 OU). Computerized visual field results revealed nonspecific diffuse alterations. Full-field electroretinogram (ERG) showed moderate diffuse rod and cone dysfunction. Visual symptoms progressively improved over the next 2 months, but ERG did not. Complete resolution was not expected due to the pre-existing eye disease. The patient was finally discharged home after a 5-week hospital stay. Conclusion: Digoxin intoxication can go unrecognized by clinicians, even in a typical presentation. The range of potential visual symptoms is far greater than isolated xanthopsia (yellow vision) classically described in textbooks. Newly introduced drugs and all symptoms must be actively sought after, because they significantly affect quality of life and global functioning, especially in the elderly population, most liable not to mention them.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

La Biblioteca de la Universitat de Girona és l'encarregada de coordinar els repositoris digitals de la Universitat. A l'inici el repositori neix de la necessitat de difondre i preservar tota la recerca de la Universitat, però mica en mica el projecte va creixent i es creen diferents repositoris per a diferents tipus de continguts. Així es creen els repositoris DUGiDocs, DUGiMedia i DUGiFonsEspecials.L'objectiu d'aquest PFC és desenvolupar un portal web amb un sistema d'indexació que permeti la cerca per diferents criteris com, per exemple, autor, matèria i títol. L'entorn ha de tenir un disseny agradable per a l'usuari final i ha de permetre obtenir les dades del repositori que se li indiquin. També ha de ser capaç de detectar els possibles duplicats en els criteris de cerca i notificar-ho a l'administrador

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We propose robust estimators of the generalized log-gamma distribution and, more generally, of location-shape-scale families of distributions. A (weighted) Q tau estimator minimizes a tau scale of the differences between empirical and theoretical quantiles. It is n(1/2) consistent; unfortunately, it is not asymptotically normal and, therefore, inconvenient for inference. However, it is a convenient starting point for a one-step weighted likelihood estimator, where the weights are based on a disparity measure between the model density and a kernel density estimate. The one-step weighted likelihood estimator is asymptotically normal and fully efficient under the model. It is also highly robust under outlier contamination. Supplementary materials are available online.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

La Biblioteca de la Universitat de Girona és l'encarregada de coordinar els repositoris digitals de la Universitat. A l'inici el repositori neix de la necessitat de difondre i preservar tota la recerca de la Universitat, però mica en mica el projecte va creixent i es creen diferents repositoris per a diferents tipus de continguts. Així es creen els repositoris DUGiDocs, DUGiMedia i DUGiFonsEspecials.L'objectiu d'aquest PFC és desenvolupar un portal web amb un sistema d'indexació que permeti la cerca per diferents criteris com, per exemple, autor, matèria i títol. L'entorn ha de tenir un disseny agradable per a l'usuari final i ha de permetre obtenir les dades del repositori que se li indiquin. També ha de ser capaç de detectar els possibles duplicats en els criteris de cerca i notificar-ho a l'administrador

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: Adverse effects of combination antiretroviral therapy (CART) commonly result in treatment modification and poor adherence. METHODS: We investigated predictors of toxicity-related treatment modification during the first year of CART in 1318 antiretroviral-naive human immunodeficiency virus (HIV)-infected individuals from the Swiss HIV Cohort Study who began treatment between January 1, 2005, and June 30, 2008. RESULTS: The total rate of treatment modification was 41.5 (95% confidence interval [CI], 37.6-45.8) per 100 person-years. Of these, switches or discontinuations because of drug toxicity occurred at a rate of 22.4 (95% CI, 19.5-25.6) per 100 person-years. The most frequent toxic effects were gastrointestinal tract intolerance (28.9%), hypersensitivity (18.3%), central nervous system adverse events (17.3%), and hepatic events (11.5%). In the multivariate analysis, combined zidovudine and lamivudine (hazard ratio [HR], 2.71 [95% CI, 1.95-3.83]; P < .001), nevirapine (1.95 [1.01-3.81]; P = .050), comedication for an opportunistic infection (2.24 [1.19-4.21]; P = .01), advanced age (1.21 [1.03-1.40] per 10-year increase; P = .02), female sex (1.68 [1.14-2.48]; P = .009), nonwhite ethnicity (1.71 [1.18-2.47]; P = .005), higher baseline CD4 cell count (1.19 [1.10-1.28] per 100/microL increase; P < .001), and HIV-RNA of more than 5.0 log(10) copies/mL (1.47 [1.10-1.97]; P = .009) were associated with higher rates of treatment modification. Almost 90% of individuals with treatment-limiting toxic effects were switched to a new regimen, and 85% achieved virologic suppression to less than 50 copies/mL at 12 months compared with 87% of those continuing CART (P = .56). CONCLUSIONS: Drug toxicity remains a frequent reason for treatment modification; however, it does not affect treatment success. Close monitoring and management of adverse effects and drug-drug interactions are crucial for the durability of CART.