996 resultados para Ecological dynamic


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The Road Rater is a dynamic deflection measuring appa-ratus for flexible base pavements. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pave-ments are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be continued to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, trouble free pavement evaluation machine. The deflection apparatus was originally front-mounted, but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution. The Road Rater provides a fast, economical, nondestructive test method to evaluate flexible pavements. Road Rater test data can be used to predict pavement life, set priorities for asphaltic concrete resurfacing, and design asphaltic concrete overlays. Temperature and seasonal variations significantly affect Road Rater deflection readings and must be considered. A nomograph included in this report adjusts for temperature, but does not correct for seasonal effect. Road Rater testing will be conducted in the spring until seasonal correction factors can be developed. The Road Rater has not successfully evaluated rigid pavements, but research will continue in this area. 1. Recommendations for continuing Road Rater research, evaluation and application are as follows:A computer program should be established to reduce Road Rater raw data (Range and Sensor reading) to HR-178 Road Rater Dynamic Deflections For Determining Structural Rating Of Flexible Pavements mean deflection (mils) and/or structural rating. This computer printout would be similar to present friction testing printouts, and would greatly reduce Road Rater data reduction manpower needs and costs. 2. Seasonal variation study should continue to develop seasonal correction factors. Seasonal test roads will be studied concurrently with routine testing during 1979 to develop this relationship. All Road Rater testing will be conducted in the spring until the seasonal relationship is established. 3. An asphaltic concrete overlay design method should be established based on Road Rater de-flection readings. The AASHTO Interim Guide for Design of Pavement Structures 1972 will be used as a base document for this study. 4. AASHTO Structural numbers should be compared to Road Rater Structural Ratings during 1979 on asphaltic concrete overlay projects. This analysis will enable us to refine Road Rater evaluation of flexible pavements. Roads will be tested before resurfacing and several months

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The molecular chaperone Hsp90-dependent proteome represents a complex protein network of critical biological and medical relevance. Known to associate with proteins with a broad variety of functions termed clients, Hsp90 maintains key essential and oncogenic signalling pathways. Consequently, Hsp90 inhibitors are being tested as anti-cancer drugs. Using an integrated systematic approach to analyse the effects of Hsp90 inhibition in T-cells, we quantified differential changes in the Hsp90-dependent proteome, Hsp90 interactome, and a selection of the transcriptome. Kinetic behaviours in the Hsp90-dependent proteome were assessed using a novel pulse-chase strategy (Fierro-Monti et al., accompanying article), detecting effects on both protein stability and synthesis. Global and specific dynamic impacts, including proteostatic responses, are due to direct inhibition of Hsp90 as well as indirect effects. As a result, a decrease was detected in most proteins that changed their levels, including known Hsp90 clients. Most likely, consequences of the role of Hsp90 in gene expression determined a global reduction in net de novo protein synthesis. This decrease appeared to be greater in magnitude than a concomitantly observed global increase in protein decay rates. Several novel putative Hsp90 clients were validated, and interestingly, protein families with critical functions, particularly the Hsp90 family and cofactors themselves as well as protein kinases, displayed strongly increased decay rates due to Hsp90 inhibitor treatment. Remarkably, an upsurge in survival pathways, involving molecular chaperones and several oncoproteins, and decreased levels of some tumour suppressors, have implications for anti-cancer therapy with Hsp90 inhibitors. The diversity of global effects may represent a paradigm of mechanisms that are operating to shield cells from proteotoxic stress, by promoting pro-survival and anti-proliferative functions. Data are available via ProteomeXchange with identifier PXD000537.

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This paper presents the results of the static and dynamic testing of a three-span continuous I-beam highway bridge. Live load stress frequency curves for selected points are shown, and the static and dynamic load distribution to the longitudinal composite beam members are given. The bridge has four traffic lanes with a roadway width of 48 ft. Six longitudinal continuous WF beams act compositely with the reinforced concrete slab to carry the live load. The beams have partial length cover plates at the piers. Previous research has indicated that beams with partial length cover plates have a very low fatigue strength. It was found in this research that the magnitude of the stresses due to actual highway loads were very much smaller than those computed from specification loading. Also, the larger stresses which were measured occurred a relatively small number of times. These data indicate that some requirements for reduced allowable stresses at the ends of cover plates are too conservative. The load distribution to the longitudinal beams was determined for static and moving loads and includes the effect of impact on the distribution. The effective composite section was found at various locations to evaluate the load distribution data. The composite action was in negative as well as positive moment regions. The load distribution data indicate that the lateral distribution of live load is consistent with the specifications, but that there is longitudinal distribution, and therefore the specifications are too conservative.

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As a result of the construction of the Saylorville Dam and Reservoir on the Des Moines River, six highway bridges are scheduled for removal. Five of these are old high-truss single-lane bridges, each bridge having several simple spans. The other bridge is a fairly modern (1955) double 4-span continuous beam-and-slab composite highway bridge. The availability of these bridges affords an unusual opportunity for study of the behavior of full-scale bridges. Because of the magnitude of the potential testing program, a feasibility study was initiated and the results are presented in this two-part final report. Part I summarizes the findings and Part II presents the supporting detailed information.

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The Road Rater is a dynamic deflection measuring apparatus for flexible base pavements. The Road Rater replaces the Benkelman Beam which was last used by the Iowa DOT in 1977. Road Rater test results correlate reasonably well (correlation coefficient = 0.83) with Benkelman Beam test data. The basic differences between the Road Rater and Benkelman Beam are as follows: 1. The Benkelman Beam uses a static 18,000 lb. load while the Road Rater uses a dynamic 800 to 2,000 lb. loading. 2. The Road Rater tests much faster and more economically than the Benkelman Beam. 3. The Road Rater better simulates a moving truck than the Benkelman Beam. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pavements are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be contined to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, troublefree pavement evaluation machine. The deflection apparatus was originally front-mounted,but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution.

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Résumé: Valoriser le géopatrimoine par la médiation indirecte et la visualisation des objets géomorphologiques Le géopatrimoine regroupe des objets géologiques lato sensu auxquels certaines valeurs sont attribuées, en fonction de leur intérêt pour la science, de leur rareté, de leurs particularités culturelles ou écologiques, etc. Valoriser le géopatrimoine signifie avant tout faire partager cette approche aux non-spécialistes, en expliquant ce qui fait la valeur de ces objets. Cette valorisation peut s'effectuer, entre autres, sous la forme d'une activité touristique et contribuer ainsi au développement régional. Faire comprendre l'origine, la singularité et la valeur des formes du relief implique le recours à une communication éducative, désignée par le terme de médiation. Les implications de la dimension éducative du processus, comme la prise en compte des connaissances et attentes du public, la création d'un environnement favorable à l'apprentissage ou l'attractivité du contenu, sont souvent négligées. Du point de vue conceptuel, un modèle de la médiation indirecte (c'est-à-dire au moyen de supports médiatiques) a été proposé et appliqué au développement empirique de produits de médiation et à leur évaluation. Ce modèle ne garantit pas la réussite de la communication éducative, mais contribue à créer un cadre favorable au processus. De plus, plusieurs lignes directrices pour le choix du type de média et sa mise en forme ont été définies sur la base d'une compilation de résultats de la psychologie cognitive sur l'usage des médias pour l'apprentissage. Des méthodes qualitatives et quantitatives variées ont été mobilisées : enquêtes par questionnaire ex situ et in situ, auprès des visiteurs de géomorphosites de montagne, réalisation de médias interactifs testés ensuite auprès de divers publics (parcours enregistré, pré- et post-questionnaires) et entretiens collectifs. Les résultats obtenus éclairent divers aspects de la problématique. L'étude du public a montré, par exemple, que le géotourisme possède un réel public parmi les visiteurs des sites de montagnes : trois-quarts d'entre eux expriment de l'intérêt pour des explications sur la géologie et l'évolution du paysage. Cette thèse a exploré ces aspects liés au processus d'apprentissage en se focalisant sur les médias visuels, surtout interactifs. La plupart des médias visuels couramment utilisés en géomorphologie ont été considérés. Le développement de versions interactives de ces médias sous forme d'applications web a fourni un aperçu concret des possibilités des nouvelles technologies. Les utilisateurs apprécient en particulier a richesse du contenu, le haut degré d'interactivité et la variété de ces applications. De tels médias incitent à visiter le site naturel et semblent aussi répondre aux intérêts de publics variés. Abstract: Geoheritage promotion through non-personal interpretation and visualisation of geomorphological features Geoheritage concerns all geological features lato sensu to which some values are attributed, according to their scientific interest, their rarity, their cultural or ecological dimensions, etc. Geoheritage promotion implies sharing this point of view with non-specialists, explaining what gives value to those objects. Geotourism is one of the many ways to achieve geoheritage promotion, while contributing also to regional development. In order to make non-specialists understand the origin, the specificity and the value of landforms, educational communication is needed, that is called interpretation (French: médiation). This education dimension has several, and often neglected, implications, like taking into account public's knowledge and expectations, creating a favourable learning environment, attractive design, etc. From the conceptual point of view, a model for non-personal interpretation has been proposed and applied for the empirical development and for the assessment of interpretive products. This model does not guarantee success of educational communication, but help creating a favourable environment for this process. Moreover, some guidelines were defined from a compilation of several results of cognitive psychology on media use for learning. They guide the choice of the kind of media and its design. Several qualitative and quantitative methods were applied: survey questionnaires ex situ and in situ by mountain geomorphosites visitors, interactive medias developed and then tested by different kinds of users (with usertracking, pre- and post-survey questionnaires), group interviews. The results answered different aspects of the research questions. Visitor surveys revealed for example that geotourism could attract many visitors of mountain areas: three quarters of them say they are interested in getting explanations about geology and landscape (in particular its dynamic dimensions). This thesis examined those aspects with a focus on visual medias, both statics and interactive. Most of currently used medias in geomorphology were considered. Interactive versions of those medias were developed in web applications; they gave a concrete overview on the opportunities that new technologies offer. The content richness, the high interaction level and the diversity of the applications are the most liked aspects by the users. Such medias drive to visit the natural site and seem to correspond to the interests of various kinds of publics. Zusammenfassung: Aufwertung des erdwissenschaftlichen Erbes durch mediale Vermittlung und Visualisierung von geomorphologischen Objekten Das erdwissenschaftliche Erbe besteht aus geologischen Gegebenheiten lato sensu, denen entsprechend ihrer Bedeutung für die Wissenschaft, ihrer Seltenheit, ihrer kulturellen oder ökologischen Besonderheiten usw. bestimmte Werte zugeordnet werden. Das erdwissenschaftliche Erbe aufzuwerten bedeutet in erster Linie, diesen Ansatz Nichtspezialisten näher zu bringen, indem ihnen erklärt wird, was den Wert dieser Gegebenheiten ausmacht. Dies kann etwa im Rahmen eines touristischen Angebots geschehen und so die regionale Entwicklung unterstützen. Um Entstehung, Besonderheit und Wert von Geländeformen verständlich zu machen, wird eine pädagogische Kommunikationsform verwendet, die als mediale Vermittlung (franz. médiation) bezeichnet wird. Die Bedeutung der pädagogischen Dimension des Vermittlungsprozesses wie etwa der Einbezug des Wissens und der Erwartungen des Publikums, die Gestaltung eines positiven Lernklimas oder die Attraktivität des Inhalts wird oft vernachlässigt. Auf konzeptueller Ebene wurde ein Modell der indirekten Interpretation erarbeitet (d. h. anhand von Medien), das bei der empirischen Entwicklung der Interpretationsprodukte und ihrer Evaluation Anwendung fand. Dieses Modell garantiert zwar nicht den Erfolg der pädagogischen Kommunikation. Es trägt aber dazu bei, einen für den Prozess günstigen Kontext zu schaffen. Des Weiteren wurden mehrere Richtlinien für die Wahl des Medientyps und dessen Ausgestaltung anhand einer Zusammenstellung von Resultaten der kognitiven Psychologie über den Gebrauch von Medien in Lernprozessen definiert. Es wurden verschiedene qualitative und quantitative Methoden eingesetzt: Befragung mittels Fragebogen der Besucher von geomorphologischen Geotopen im Gebirge - ex situ und in situ -, Erarbeitung von interaktiven Medien, die anschliessend anhand verschiedener Zielgruppen gestestet wurden (Aufnahme des Besuchparcours, Vor- und Nachfragebögen) sowie kollektive Interviews. Die Ergebnisse geben Aufschluss zu verschiedenen Aspekten der Fragestellung. Die Befragung des Publikums hat zum Beispiel deutlich gemacht, dass der Geotourismus unter den Besuchern von Berggebieten tatsächlich auf eine Nachfrage stösst: drei Viertel von ihnen zeigen ein Interesse für Erläuterungen zur Geologie und der Landschaftsentwicklung. Die vorliegende Doktorarbeit hat die genannten Aspekte der Lernprozesse untersucht, wobei der Fokus auf visuellen, insbesondere interaktiven Medien lag. Die meisten gängigen visuellen Medien der Geomorphologie wurden berücksichtigt. Die Entwicklung von interaktiven Versionen dieser Medien in Form von Web-Anwendungen hat die Möglichkeiten der neuen Technologien veranschaulicht. Die Benutzer schätzten insbesondere die Vielfalt des Inhalts, die hohe Interaktivität und die Diversität dieser Anwendungen. Solche Medien laden dazu ein, ein Naturgebiet zu besuchen und scheinen den Interessen der verschiedenen Publikumsgruppen entgegenzukommen.

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The design of satisfactory supporting and expansion devices for highway bridges is a problem which has concerned bridge design engineers for many years. The problems associated with these devices have been emphasized by the large number of short span bridges required by the current expanded highway program of expressways and interstate highways. The initial objectives of this investigation were: (1) To review and make a field study of devices used for the support of bridge superstructures and for provision of floor expansion; (2) To analyze the forces or factors which influence the design and behavior of supporting devices and floor expansion systems; and (3) To ascertain the need for future research particularly on the problems of obtaining more economical and efficient supporting and expansion devices, and determining maximum allowable distance between such devices. The experimental portion was conducted to evaluate one of the possible simple and economical solutions to the problems observed in the initial portion. The investigation reported herein is divided into four major parts or phases as follows: (1) A review of literature; (2) A survey by questionnaire of design practice of a number of state highway departments and consulting firms; (3) Field observation of existing bridges; and, (4) An experimental comparison of the dynamic behavior of rigid and elastomeric bearings.

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The purpose of this study is to introduce and describe a newly developed index using foot pressure analysis to quantify the degree of equinus gait in children with cerebral palsy before and after injection with botulinum toxin. Data were captured preinjection and 12 weeks postinjection. Ten children aged 2(1/2) to 6(1/2) years took part (5 boys and 5 girls). Three of them had a diagnosis of spastic diplegia and 7 of congenital hemiplegia. In total, 13 limbs were analyzed. After orientation and segmentation of raw pedobarographic data, we determined a dynamic foot pressure index graded 0 to 100 that quantified the relative degree of heel and forefoot contact during stance. These data were correlated (Pearson correlation) with clinical measurements of dorsiflexion at the ankle (on a slow and fast stretch) and video observation (using the Observational Gait Scale). Pedobarograph data were strongly correlated with both the Observational Gait Scale scores (R = 0.79, P < 0.005) and clinical measurements of dorsiflexion on a fast stretch, which is reflective of spasticity (R = 0.70, P < 0.005). We demonstrated the index's sensitivity in detecting changes in spasticity and good correlation with video observations seems to indicate this technique's potential validity. When manipulated and segmented appropriately, and with the development of a simple ordinal index, we found that foot pressure data provided a useful tool in tracking changes in patients with spastic equinus.

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The asphalt concrete (AC) dynamic modulus (|E*|) is a key design parameter in mechanistic-based pavement design methodologies such as the American Association of State Highway and Transportation Officials (AASHTO) MEPDG/Pavement-ME Design. The objective of this feasibility study was to develop frameworks for predicting the AC |E*| master curve from falling weight deflectometer (FWD) deflection-time history data collected by the Iowa Department of Transportation (Iowa DOT). A neural networks (NN) methodology was developed based on a synthetically generated viscoelastic forward solutions database to predict AC relaxation modulus (E(t)) master curve coefficients from FWD deflection-time history data. According to the theory of viscoelasticity, if AC relaxation modulus, E(t), is known, |E*| can be calculated (and vice versa) through numerical inter-conversion procedures. Several case studies focusing on full-depth AC pavements were conducted to isolate potential backcalculation issues that are only related to the modulus master curve of the AC layer. For the proof-of-concept demonstration, a comprehensive full-depth AC analysis was carried out through 10,000 batch simulations using a viscoelastic forward analysis program. Anomalies were detected in the comprehensive raw synthetic database and were eliminated through imposition of certain constraints involving the sigmoid master curve coefficients. The surrogate forward modeling results showed that NNs are able to predict deflection-time histories from E(t) master curve coefficients and other layer properties very well. The NN inverse modeling results demonstrated the potential of NNs to backcalculate the E(t) master curve coefficients from single-drop FWD deflection-time history data, although the current prediction accuracies are not sufficient to recommend these models for practical implementation. Considering the complex nature of the problem investigated with many uncertainties involved, including the possible presence of dynamics during FWD testing (related to the presence and depth of stiff layer, inertial and wave propagation effects, etc.), the limitations of current FWD technology (integration errors, truncation issues, etc.), and the need for a rapid and simplified approach for routine implementation, future research recommendations have been provided making a strong case for an expanded research study.

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We present here a dynamic model of functional equilibrium between keratinocyte stem cells, transit amplifying populations and cells that are reversibly versus irreversibly committed to differentiation. According to this model, the size of keratinocyte stem cell populations can be controlled at multiple levels, including relative late steps in the sequence of events leading to terminal differentiation and by the influences of a heterogeneous extra-cellular environment. We discuss how work in our laboratory, on the interconnection between the cyclin/CDK inhibitor p21WAF1/Cip1 and the Notch1 signaling pathways, provides strong support to this dynamic model of stem cell versus committed and/or differentiated keratinocyte populations.

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Polychlorinated trityl radicals bearing carboxylate substituents are water soluble persistent radicals that can be used for dynamic nuclear polarization. In contrast to other trityl radicals, the polarization mechanism differs from the classical solid effect. DFT calculations performed to rationalize this behaviour support the hypothesis that polarization is transferred from the unpaired electron to chlorine nuclei and from these to carbon by spin diffusion. The marked differences observed between neutral and anionic forms of the radical will be discussed.

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Chemical shifts of protons can report on metabolic transformations such as the conversion of choline to phosphocholine. To follow such processes in vivo, magnetization can be enhanced by dynamic nuclear polarization (DNP). We have hyperpolarized in this manner nitrogen-15 spins in (15)N-labeled choline up to 3.3% by irradiating the 94 GHz electron spin resonance of admixed TEMPO nitroxide radicals in a magnetic field of 3.35 T during ca. 3 h at 1.2 K. The sample was subsequently transferred to a high-resolution magnet, and the enhanced polarization was converted from (15)N to methyl- and methylene protons, using the small (2,3)J((1)H,(15)N) couplings in choline. The room-temperature lifetime of nitrogen polarization in choline, T(1)((15)N) approximately 200 s, could be considerably increased by partial deuteration of the molecule. This procedure enables studies of choline metabolites in vitro and in vivo using DNP-enhanced proton NMR.

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Oil-collecting bees are found worldwide and always in association with particular oil-producing flowers. In the Western Palearctic, three oil-collecting bee species within the genus Macropis (Hymenoptera, Melittidae) interact in a tight pollination mutualism with species of the only European oil-producing plant genus Lysimachia L. (Myrsinaceae). Two of these oil-collecting bees (Macropis europaea and Macropis fulvipes) show overlapping geographic distributions, comparable morphologies, and similar ecological characteristics (e.g., habitat type, floral preferences). In view of these similarities, we presume that hybridization should occur between the two species unless potential variation among the species' ecological niches prevents it, simultaneously decreasing competition for resources. Using modern genetic analyses and ecological niche modeling on a large bee sampling throughout Europe, we discuss new perspectives on the ecology and evolutionary history of this mutualism.