Concrete deep beams with small shear span-to-depth (a/d) ratios are common elements in structures. However, there are few experimental results on the behaviour of FRP reinforced concrete deep beams and no specific modelling techniques exist in design codes for such members. The objectives of this study were to examine the shear behaviour of FRP reinforced concrete deep beams containing no web reinforcement and to develop a modelling technique. Test results of 12 large-scale specimens are reported where the primary variables included the a/d ratio, reinforcement ratio, member height, and concrete strength. The results showed that an arch mechanism was able to form in FRP reinforced concrete beams having a/d 2.1. A strut and tie modelling procedure adapted from CSA A23.3-04 was capable of accurately predicting the capacity of FRP reinforced concrete deep beams containing no web reinforcement while sectional shear models gave poor, but conservative, predictions. / Structural Engineering

<p>Uppsatsens syfte är att analysera och diskutera vad som legat till grund för organisering av arméns insatsförband insatsorganisations år 2009 (IO 09). Hur ser organisationsstrukturen ut och vilka faktorer har påverkat organiseringen av IO 09? Uppgiftens komplexitet innebar att jag närmade mig problemformuleringen från olika perspektiv. Studien omfattar därmed en mångsidig kvalitativ analys av data från både styrdokument och intervjuer.</p><p>Studien visar att det framförallt är de klassiska ”byråkratiska teoretiska” perspektiven som dominerar organisationsdesignen inom arméns insatsorganisation 2009. Vidare förefaller det finnas en arketyp för hur ett förband i armén skall vara organiserat. Denna arketyp omfattas sannolikt av en organisationsstruktur om fyra ledningsnivåer och ett kontrollspann om fyra eller fem enheter i alla nivåer. Signifikant för maskinbyråkratimodellen, vilken identifierats i nio av tio organisationsstrukturer i IO 09, är att denna organisationsdesign underlättar tydliga och klara ledningsförhållanden. Däremot har maskinbyråkratimodellen en del nackdelar såsom att modellen anses vara rigid och svår att förändra. Studien konstaterar därmed en intressant paradox d.v.s. kravet på att organisationerna i IO 09 skall vara modulära och flexibla samtidigt som organisationsstrukturerna i IO 09 antyder något annat. Ett annat resultat som studien visar är att det framförallt synes varit mänskliga faktorer tillsammans med omgivningskaraktäristiska faktorer som dominerat ”processerna” i organiseringen av IO 09, därmed också i allra högsta grad resultatet av hur arméns insatsorganisation 2009 är organiserad.</p> / <p>The purpose of this essay is to analyse and discuss what has been the basis of the organization of the mission-based armed forces in the year of the mission-based organization 2009 (IO 09). What does the organizational structure look like and what factors have affected the organization of IO 09? The complexity of the task demanded an approach to problem formulation from various perspectives. Thus, the study includes a diversified qualitative analysis of data collected from governing documents as well as interviews.</p><p>The study shows that, above all, it is the classic “bureaucratic theoretical” perspectives that dominate the organizational design within the mission-based organization 2009. Furthermore, there seems to exist an archetype with respect to how an army force battalion unit should be organized. This archetype does most likely represent an organizational structure comprised of four levels of leadership and a span of control of four or five units operating at all levels. Significant to the machine bureaucracy model, which has been identified in nine out of ten organizational structures in IO 09, is that this organizational design facilitates distinct and clear leadership conditions. However, the machine bureaucracy model demonstrates some disadvantages such as the fact that it is considered to be rigid and difficult to change. Hence, the study reveals an interesting paradox, that is, the requirements stipulated for the organizations in IO 09 are supposed to be modular and flexible while the organizational structures in IO 09 suggest something else. An additional result showed by the study is that, primarily, it appears that human factors combined with environmental characteristic factors have dominated the “processes” with regard to the organization of IO 09. Consequently, these factors have also seem to generated the outcome with regard to how the army’s mission-based organization 2009 has been organized.</p>

This PhD thesis, consisting of an introduction, four papers, and some supplementary results, studies the problem of finding an optimal realization of a given finite metric space: a weighted graph which preserves the metric's distances and has minimal total edge weight. This problem is known to be NP-hard, and solutions are not necessarily unique. It has been conjectured that extremally weighted optimal realizations may be found as subgraphs of the hereditarily optimal realization Γd, a graph which in general has a higher total edge weight than the optimal realization but has the advantages of being unique, and possible to construct explicitly via the tight span of the metric. In Paper I, we prove that the graph Γd is equivalent to the 1-skeleton of the tight span precisely when the metric considered is totally split-decomposable. For the subset of totally split-decomposable metrics known as consistent metrics this implies that Γd is isomorphic to the easily constructed Buneman graph. In Paper II, we show that for any metric on at most five points, any optimal realization can be found as a subgraph of Γd. In Paper III we provide a series of counterexamples; metrics for which there exist extremally weighted optimal realizations which are not subgraphs of Γd. However, for these examples there also exists at least one optimal realization which is a subgraph. Finally, Paper IV examines a weakened conjecture suggested by the above counterexamples: can we always find some optimal realization as a subgraph in Γd? Defining extremal optimal realizations as those having the maximum possible number of shortest paths, we prove that any embedding of the vertices of an extremal optimal realization into Γd is injective. Moreover, we prove that this weakened conjecture holds for the subset of consistent metrics which have a 2-dimensional tight span

Using Hebb’s (1961) paradigm, it has been shown that older adults (OAs) fail to learn recurrent visuospatial supra-span sequence information (Turcotte, Gagnon, & Poirier, 2005); a deficit which has not been demonstrated on verbal versions of the same task or in younger adults (YAs). Since the Hebb paradigm is thought to rely on working memory and thus attention (Conway & Engle, 1996), one interpretation concerns an OA’s capacity to allocate the necessary attentional resources to carry out the various components of the task. Five studies investigated this proposal. The first three (Article 1) examined attention in a general manner by reducing the amount of attentional resources that a YA could devote to carrying out the visuospatial Hebb supra-span sequence learning task through the implementation of a verbal dual task (DT) procedure. The fourth (Article 2) further investigated the role of attention by using a DT induced at retrieval that overlapped extensively with the requirements (spatial and response features) of the visuospatial Hebb task. The final study (Article 3) aimed to use our previous findings to demonstrate learning among OAs in a visuospatial Hebb learning paradigm in which the motor response was replaced by a verbal response. Our findings confirm that attentional resources employed at the retrieval phase of the task appear to be particularly important for the demonstration of visuospatial sequence learning. The inclusion of a spatial and motor based DT at recall eliminated learning of the repeated sequence in YAs. Interestingly, the learning deficit of OAs was partially eliminated when the motor and spatial requirements at retrieval were reduced. Our findings offer strong support to the contention that supra-span learning of the Hebb type is not altered by the effect of age. However, learning deficits can be observed among OAs when the retrieval component of the task overly taxes attention-related processes. In the case of the visuospatial sequences, the basis of the deficit likely concerns an individual’s capacity to discriminate between responses made to previously presented sequences versus those that need to be made in reaction to the just seen sequence.

Using Hebb’s (1961) paradigm, it has been shown that older adults (OAs) fail to learn recurrent visuospatial supra-span sequence information (Turcotte, Gagnon, & Poirier, 2005); a deficit which has not been demonstrated on verbal versions of the same task or in younger adults (YAs). Since the Hebb paradigm is thought to rely on working memory and thus attention (Conway & Engle, 1996), one interpretation concerns an OA’s capacity to allocate the necessary attentional resources to carry out the various components of the task. Five studies investigated this proposal. The first three (Article 1) examined attention in a general manner by reducing the amount of attentional resources that a YA could devote to carrying out the visuospatial Hebb supra-span sequence learning task through the implementation of a verbal dual task (DT) procedure. The fourth (Article 2) further investigated the role of attention by using a DT induced at retrieval that overlapped extensively with the requirements (spatial and response features) of the visuospatial Hebb task. The final study (Article 3) aimed to use our previous findings to demonstrate learning among OAs in a visuospatial Hebb learning paradigm in which the motor response was replaced by a verbal response. Our findings confirm that attentional resources employed at the retrieval phase of the task appear to be particularly important for the demonstration of visuospatial sequence learning. The inclusion of a spatial and motor based DT at recall eliminated learning of the repeated sequence in YAs. Interestingly, the learning deficit of OAs was partially eliminated when the motor and spatial requirements at retrieval were reduced. Our findings offer strong support to the contention that supra-span learning of the Hebb type is not altered by the effect of age. However, learning deficits can be observed among OAs when the retrieval component of the task overly taxes attention-related processes. In the case of the visuospatial sequences, the basis of the deficit likely concerns an individual’s capacity to discriminate between responses made to previously presented sequences versus those that need to be made in reaction to the just seen sequence.

Das autobiografische Gedächtnis findet als Thema der psychologischen Grundlagenforschung immer größere Aufmerksamkeit. Vorliegende Arbeiten haben zur differenzierten Charakterisierung des autobiografischen Wissensbestands in seiner Gesamtheit und der autobiografischen Erinnerungen als dessen Elemente beigetragen. Neben Fragen der Repräsentation liegt es nahe, Besonderheiten des autobiografischen Gedächtnisses über die Lebensspanne hinweg zu betrachten. Schwerpunkt der Analysen ist die Verteilung individueller Erinnerungen an Ereignisse über den gesamten Lebenslauf. Das zentrale Merkmal der Verteilung ist der relative Anstieg der Zahl von Erinnerungen im Zeitraum zwischen dem 10.und dem 30. Lebensjahr, vergleicht man diese mit der Zahl von Erinnerungen in den Lebensabschnitten direkt vor diesem und direkt im Anschluss an diesen Zeitabschnitt. Die Analyse dieser robusten und reliablen Besonderheit der Verteilung autobiografischer Erinnerungen - des bump - ist Gegenstand der vorliegenden empirischen Arbeit. Im Gegensatz zu bisherigen Studien galt unser Interesse aber nicht nur frei wählbaren Erinnerungen. Es stand vielmehr die Klasse der lebendigen autobiografischen Erinnerungen im Mittelpunkt, die innerhalb des autobiografischen Wissensbestands unterschiedlichen, aber in der individuellen Entwicklung über die Lebensspanne relevanten, von uns vorgegebenen Themen zuzuordnen sind (Arbeitsleben Beziehung zu Geschwistern, Beziehung zu Freunden und Bekannten, zusätzlich: Allgemeine lebendige Erinnerungen ohne thematische Bindung). Die berichteten Erinnerungen verteilten sich insgesamt in typischer Weise über die Lebensspanne. Unabhängig von themenspezifischen Aspekten zeigte sich auch in der vorliegenden Studie der bump in der Gesamtverteilung autobiografischer Erinnerungen über die Lebensspanne. Bei den themenspezifischen Verteilungen waren jedoch Abweichungen von der erwarteten Verteilungsform festzustellen. Der bump ließ sich bei den Themen Arbeitsleben und Freunde, Bekannte nur in abgeschwächter Form identifizieren, beim Thema Zwillinge war er dagegen auf einen früheren Zeitpunkt als erwartet datiert und sehr ausgeprägt. Die Verteilung im Themenblock Allgemein deckte sich weitgehend mit dem erwarteten Verteilungsmuster. Durch Einbindung in ein größeres Forschungsprojekt konnten die Verteilungen in den Themen Zwillinge und Arbeitsleben im Kontext relevanter biografischer Informationen weiter analysiert und z.T. auf lebensalters- und kontextgebundene Entwicklungen zurückgeführt werden. Die Ergebnisse der Studie werden im Hinblick auf ihre theoretischen Implikationen und ihre Bedeutung für nachfolgende Arbeiten aus einer entwicklungspsychologischen Perspektive diskutiert.

published_or_final_version / Social Work / Master / Master of Social Sciences

La première augmentation de la longévité en laboratoire fût observée à la suite d’une intervention nutritionnelle consistant en une réduction de l’apport alimentaire chez le rat. Plus tard, ce phénomène a été reproduit dans de très nombreuses espèces et référé en tant que restriction calorique. Le développement des techniques de biologie moléculaire moderne a permis de montrer dans des organismes modèles simples que cette flexibilité du processus de vieillissement était régulée par des facteurs génétiques. De fait, plusieurs mécanismes cellulaires ont alors pu être identifiés comme responsables de ce contrôle du vieillissement. Ces voies de régulation ont révélées être conservées entre les espèces, depuis les levures jusqu’aux organismes multicellulaires tels que le nématode, la mouche ou la souris, suggérant l’existence d’un programme universel de vieillissement dans le vivant. La levure s’est avéré à plusieurs reprises être un modèle puissant et fiable pour la découverte de gènes impliqués dans ce phénomène. Mon étude a consisté au développement d’un nouveau modèle unicellulaire d’étude du vieillissement à travers l’espèce Schizosaccharomyces pombe appelée aussi levure à fission. La première étape de mon travail a montré que les voies de détection des nutriments gouvernées par la sérine/thréonine protéine kinase A (Pka1) et la sérine/thréonine kinase Sck2 contrôlent le vieillissement chronologique de ces cellules comme il était connu dans la levure Saccharomyces cerevisiae. Ceci permit de valider l’utilisation de la levure à fission pour l’étude du vieillissement. Ensuite, nous avons analysé plus en détail l’effet pro-vieillissement du glucose en étudiant le rôle de sa détection par le récepteur membranaire Git3 couplé à la protéine G (Gpa2) en amont de la kinase Pka1. La perte du signal du glucose par la délétion de Git3 imite partiellement l’effet d’augmentation de longévité obtenu par baisse de la concentration en glucose dans le milieu. De plus, l’effet néfaste du signal du glucose est maintenu en absence de tout métabolisme du glucose suite à la mutation des hexokinases, premières enzymes de la glycolyse. L’ensemble de ces résultats suggèrent que la signalisation du glucose est prédominante sur son métabolisme pour son effet pro-vieillissement. D’autre part, à la fois la suppression de cette signalisation et la baisse de niveau de glucose disponible allongent la durée de vie en corrélation avec une augmentation de la résistance au stress, une hausse d’activité mitochondriale et une baisse de production de radicaux libres. Finalement, le criblage d’une banque de surexpression d’ADNc a permis d’identifier plusieurs gènes candidats responsables de ces effets en aval de la voie de signalisation Git3/PKA. La recherche sur les mécanismes moléculaires du vieillissement propose une nouvelle approche, un nouvel angle de vue, pour la compréhension des fonctions cellulaires et promet d’apporter de précieuses clefs pour mieux comprendre certaines maladies. En effet, le vieillissement est la première cause d’apparition de nombreuses affections comme les cancers, les maladies cardiovasculaires et métaboliques ou les maladies neurodégénératives tels que les syndromes d’Alzheimer et de Parkinson. / The first increase in life span due to man’s intervention was obtained with rats subjected to a diet reduced in calorie intake. Later, this phenomenon was repeated with many other species and referred as diet restriction or calorie restriction. The development of modern Molecular Biology approaches and the use of simple model organisms demonstrated that the rate of aging was regulated by genetic traits. Indeed, several cellular mechanisms were identified as responsible for the control of aging. These regulatory pathways appear to be conserved throughout species, from yeast to multicellular organisms like nematode, fly and mice, thus suggesting the existence of a universal program of aging. Yeast proved several times to be a powerful and reliable model for discovering genes involved in the regulation of aging. My study consisted in developing Schizosaccharomyces pombe (also called fission yeast) as a new unicellular model to study aging. The first step of my work was to show that pathways of nutrient detection through kinases involving Pka1 and Sck2 control chronological aging in S. pombe, as it was previously demonstrated in Saccharomyces cerevisiae. This first work validated the use of fission yeast for the study of aging. Subsequently, we analysed in more detail the pro-aging effect of glucose focusing on the role of its signalling through the G-protein Gpa2-coupled membrane receptor Git3, which acts upstream of Pka1. The loss of the glucose signal due to deletion of Git3 mimics partially the effect of increasing longevity by reducing glucose in the medium. Moreover, detrimental effects of glucose signal are maintained in absence of sugar metabolism following loss of hexokinases, the first enzymes of glycolysis. Together, these results suggest that the pro-aging effects of glucose signalling are predominant over those due to metabolism of this sugar. Moreover, both obliteration of this signalling pathway and decrease of glucose availability extend life span, and correlate with an increase in stress resistance, in mitochondrial activity and a lower production of free radicals. Finally, screening a cDNA-overexpression library allowed us to identify several genes candidates responsible for the effects on longevity downstream of Git3/Pka1. Research in the molecular mechanisms of aging propose holds the promise to bring precious clues as to this mysterious processes affecting all living creatures, and paves the way to unravel the underlying causes of many human diseases. Indeed, aging is the first cause of numerous late-onset pathologies including cancers, cardiovascular diseases or neurodegenerative diseases like Alzheimer and Parkinson syndromes.

No description available.

A stereoselective synthesis of (25S)-Δ1-, (25S)-Δ1,4-, (25S)-Δ1,7-, (25S)-Δ8(14)-, (25S)-Δ4,6,8(14)-dafachronic acid, methyl (25S)-Δ1,4-dafachronate and (25S)-5α-hydroxy-3,6-dioxocholest-7-en-26-oic acid is described. (25S)-Δ1,4-Dafachronic acid and its methyl ester are natural products isolated from corals and have been obtained by synthesis for the first time. (25S)-5α-Hydroxy-3,6-dioxocholest-7-en-26-oic acid represents a promising synthetic precursor for cytotoxic marine steroids. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.