Southern Annular Mode and westerly-wind-driven changes in Indian-Atlantic exchange mechanisms

The dynamical link between the Indian Ocean and Atlantic Meridional Overturning Circulation (AMOC) remains poorly understood. This partly arises from the complex Agulhas leakage, which occurs via rings, cyclones, and non-eddy flux. Hindcast simulations suggest that leakage has recently increased but have not decomposed this signal into its constituent mechanisms. Here these are isolated in a realistic ocean model. Increases in simulated leakage are attributed to stronger eddy and non-eddy-driven transports, and a strong warming and salinification, especially within Agulhas rings. Variability in both regimes is associated with strengthening Indian Ocean westerly winds, reflecting an increasingly positive Southern Annular Mode. While eddy and non-eddy flux signals are tied through turbulent eddy dissipation, the ratio between the two varies decadally. Consequently, while altimetry suggests a recent increase in retroflection turbulence and implied leakage, non-eddy flux may also play a significant role in modulating the leakage AMOC connection.

Strengthening of timber structures with glued-in rods

The research and development of connecting and strengthening timber structural elements with glued-inrods (GiR) has been ongoing since the 1980s. Despite many successful applications in practice, agreement regarding design criteria has not been reached. This state-of-the-art review summarises results from both research and practical applications regarding connections and reinforcement with GiR. The review considers manufacturing methods, mechanisms and parameters governing the performance and strength of GiR, theoretical approaches to estimate their load-bearing capacity and existing design recommendations.

Molecular mechanisms controlling synaptic recruitment of GluA4 subunit-containing AMPAreceptors

Synaptic recruitment of AMPA receptors (AMPARs) represents a key postsynaptic mechanism driving functional development and maturation of glutamatergic synapses. At immature hippocampal synapses, PKA-driven synaptic insertion of GluA4 is the predominant mechanism for synaptic reinforcement. However, the physiological significance and molecular determinants of this developmentally restricted form of plasticity are not known. Here we show that PKA activation leads to insertion of GluA4 to synaptic sites with initially weak or silent AMPAR-mediated transmission. This effect depends on a novel mechanism involving the extreme C-terminal end of GluA4, which interacts with the membrane proximal region of the C-terminal domain to control GluA4 trafficking. In the absence of GluA4, strengthening of AMPAR-mediated transmission during postnatal development was significantly delayed. These data suggest that the GluA4-mediated activation of silent synapses is a critical mechanism facilitating the functional maturation of glutamatergic circuitry during the critical period of experience-dependent fine-tuning.

Molecular mechanisms involved in T cell migration across the blood-brain barrier

In the healthy individuum lymphocyte traffic into the central nervous system (CNS) is very low and tightly controlled by the highly specialized blood-brain barrier (BBB). In contrast, under inflammatory conditions of the CNS such as in multiple sclerosis or in its animal model experimental autoimmune encephalomyelitis (EAE) circulating lymphocytes and monocytes/macrophages readily cross the BBB and gain access to the CNS leading to edema, inflammation and demyelination. Interaction of circulating leukocytes with the endothelium of the blood-spinal cord and blood-brain barrier therefore is a critical step in the pathogenesis of inflammatory diseases of the CNS. Leukocyte/endothelial interactions are mediated by adhesion molecules and chemokines and their respective chemokine receptors. We have developed a novel spinal cord window preparation, which enables us to directly visualize CNS white matter microcirculation by intravital fluorescence videomicroscopy. Applying this technique of intravital fluorescence videomicroscopy we could provide direct in vivo evidence that encephalitogenic T cell blasts interact with the spinal cord white matter microvasculature without rolling and that alpha4-integrin mediates the G-protein independent capture and subsequently the G-protein dependent adhesion strengthening of T cell blasts to microvascular VCAM-1. LFA-1 was found to neither mediate the G-protein independent capture nor the G- protein dependent initial adhesion strengthening of encephalitogenic T cell blasts within spinal cord microvessel, but was rather involved in T cell extravasation across the vascular wall into the spinal cord parenchyme. Our observation that G-protein mediated signalling is required to promote adhesion strengthening of encephalitogenic T cells on BBB endothelium in vivo suggested the involvement of chemokines in this process. We found functional expression of the lymphoid chemokines CCL19/ELC and CCL21/SLC in CNS venules surrounded by inflammatory cells in brain and spinal cord sections of mice afflicted with EAE suggesting that the lymphoid chemokines CCL19 and CCL21 besides regulating lymphocyte homing to secondary lymphoid tissue might be involved in T lymphocyte migration into the immuneprivileged CNS during immunosurveillance and chronic inflammation. Here, I summarize our current knowledge on the sequence of traffic signals involved in T lymphocyte recruitment across the healthy and inflamed blood-brain and blood-spinal cord barrier based on our in vitro and in vivo investigations.

Mechanisms that Trigger a Good Health-Care Response to Intimate Partner Violence in Spain. Combining Realist Evaluation and Qualitative Comparative Analysis Approaches

Background. Health care professionals, especially those working in primary health-care services, can play a key role in preventing and responding to intimate partner violence. However, there are huge variations in the way health care professionals and primary health care teams respond to intimate partner violence. In this study we tested a previously developed programme theory on 15 primary health care center teams located in four different Spanish regions: Murcia, C Valenciana, Castilla-León and Cantabria. The aim was to identify the key combinations of contextual factors and mechanisms that trigger a good primary health care center team response to intimate partner violence. Methods. A multiple case-study design was used. Qualitative and quantitative information was collected from each of the 15 centers (cases). In order to handle the large amount of information without losing familiarity with each case, qualitative comparative analysis was undertaken. Conditions (context and mechanisms) and outcomes, were identified and assessed for each of the 15 cases, and solution formulae were calculated using qualitative comparative analysis software. Results. The emerging programme theory highlighted the importance of the combination of each team’s self-efficacy, perceived preparation and women-centredness in generating a good team response to intimate partner violence. The use of the protocol and accumulated experience in primary health care were the most relevant contextual/intervention conditions to trigger a good response. However in order to achieve this, they must be combined with other conditions, such as an enabling team climate, having a champion social worker and having staff with training in intimate partner violence. Conclusions. Interventions to improve primary health care teams’ response to intimate partner violence should focus on strengthening team’s self-efficacy, perceived preparation and the implementation of a woman-centred approach. The use of the protocol combined with a large working experience in primary health care, and other factors such as training, a good team climate, and having a champion social worker on the team, also played a key role. Measures to sustain such interventions and promote these contextual factors should be encouraged.

Structural differentiation and corporate venturing : the moderating role of formal and informal integration mechanisms

Research has suggested that corporate venturing is crucial to strategic renewal and firm performance, yet scholars still debate the appropriate organizational configurations to facilitate the creation of new businesses in existing organizations. Our study investigates the effectiveness of combining structural differentiation with formal and informal organizational as well as top management team integration mechanisms in establishing an appropriate context for venturing activities. Our findings suggest that structural differentiation has a positive effect on corporate venturing. In addition, our study indicates that a shared vision has a positive effect on venturing in a structurally differentiated context. Socially integrated senior teams and cross-functional interfaces, however, are ineffective integration mechanisms for establishing linkages across differentiated units and for successfully pursuing corporate venturing.

Review of strengthening techniques using externally bonded fiber reinforced polymer composites

This report reviews the selection, design, and installation of fiber reinforced polymer systems for strengthening of reinforced concrete or pre-stressed concrete bridges and other structures. The report is prepared based on the knowledge gained from worldwide experimental research, analytical work, and field applications of FRP systems used to strengthen concrete structures. Information on material properties, design and installation methods of FRP systems used as external reinforcement are presented. This information can be used to select an FRP system for increasing the strength and stiffness of reinforced concrete beams or the ductility of columns, and other applications. Based on the available research, the design considerations and concepts are covered in this report. In the next stage of the project, these will be further developed as design tools. It is important to note, however, that the design concepts proposed in literature have not in many cases been thoroughly developed and proven. Therefore, a considerable amount of research work will be required prior to development of the design concepts into practical design tools, which is a major goal of the current research project. The durability and long-term performance of FRP materials has been the subject of much research, which still are on going. Long-term field data are not currently available, and it is still difficult to accurately predict the life of FRP strengthening systems. The report briefly addresses environmental degradation and long-term durability issues as well. A general overview of using FRP bars as primary reinforcement of concrete structures is presented in Chapter 8. In Chapter 9, a summary of strengthening techniques identified as part of this initial stage of the research project and the issues which require careful consideration prior to practical implementation of these identified techniques are presented.

User friendly guide for rehabilitation or strengthening of bridge structures using fiber reinforced polymer composites

A worldwide interest is being generated in the use of fibre reinforced polymer composites (FRP) in rehabilitation of reinforced concrete structures. As a replacement for the traditional steel plates or external post-tensioning in strengthening applications, various types of FRP plates, with their high strength to weight ratio and good resistance to corrosion, represent a class of ideal material in external retrofitting. Within the last ten years, many design guidelines have been published to provide guidance for the selection, design and installation of FRP systems for external strengthening of concrete structures. Use of these guidelines requires understanding of a number of issues pertaining to different properties and structural failure modes specific to these materials. A research initiative funded by the CRC for Construction Innovation was undertaken (primarily at RMIT) to develop a decision support tool and a user friendly guide for use of fibre reinforced polymer composites in rehabilitation of concrete structures. The user guidelines presented in this report were developed after industry consultation and a comprehensive review of the state of the art technology. The scope of the guide was mainly developed based on outcomes of two workshops with Queensland Department of Main Roads (QDMR). The document covers material properties, recommended construction requirements, design philosophy, flexural, shear and torsional strengthening of beams and strengthening of columns. In developing this document, the guidelines published on FIB Bulletin 14 (2002), Task group 9.3, International Federation of Structural Concrete (FIB) and American Concrete Institute Committee 440 report (2002) were consulted in conjunction with provisions of the Austroads Bridge design code (1992) and Australian Concrete Structures code AS3600 (2002). In conclusion, the user guide presents design examples covering typical strengthening scenarios.

Final report : a software diagnostic tool for evaluating distress mechanisms in bridges exposed to aggressive environments

Durability issues of reinforced concrete construction cost millions of dollars in repair or demolition. Identification of the causes of degradation and a prediction of service life based on experience, judgement and local knowledge has limitations in addressing all the associated issues. The objective of this CRC CI research project is to develop a tool that will assist in the interpretation of the symptoms of degradation of concrete structures, estimate residual capacity and recommend cost effective solutions. This report is a documentation of the research undertaken in connection with this project. The primary focus of this research is centred on the case studies provided by Queensland Department of Main Roads (QDMR) and Brisbane City Council (BCC). These organisations are endowed with the responsibility of managing a huge volume of bridge infrastructure in the state of Queensland, Australia. The main issue to be addressed in managing these structures is the deterioration of bridge stock leading to a reduction in service life. Other issues such as political backlash, public inconvenience, approach land acquisitions are crucial but are not within the scope of this project. It is to be noted that deterioration is accentuated by aggressive environments such as salt water, acidic or sodic soils. Carse, 2005, has noted that the road authorities need to invest their first dollars in understanding their local concretes and optimising the durability performance of structures and then look at potential remedial strategies.

Towards a rule-based matrix for evaluating distress mechanisms in bridges

The effective management of bridge stock involves making decisions as to when to repair, remedy, or do nothing, taking into account the financial and service life implications. Such decisions require a reliable diagnosis as to the cause of distress and an understanding of the likely future degradation. Such diagnoses are based on a combination of visual inspections, laboratory tests on samples and expert opinions. In addition, the choice of appropriate laboratory tests requires an understanding of the degradation mechanisms involved. Under these circumstances, the use of expert systems or evaluation tools developed from “realtime” case studies provides a promising solution in the absence of expert knowledge. This paper addresses the issues in bridge infrastructure management in Queensland, Australia. Bridges affected by alkali silica reaction and chloride induced corrosion have been investigated and the results presented using a mind mapping tool. The analysis highights that several levels of rules are required to assess the mechanism causing distress. The systematic development of a rule based approach is presented. An example of this application to a case study bridge has been used to demonstrate that preliminary results are satisfactory.

A framework for predicting the residual load carrying capacity of concrete structures exposed to aggressive environments

Reinforced concrete structures are susceptible to a variety of deterioration mechanisms due to creep and shrinkage, alkali-silica reaction (ASR), carbonation, and corrosion of the reinforcement. The deterioration problems can affect the integrity and load carrying capacity of the structure. Substantial research has been dedicated to these various mechanisms aiming to identify the causes, reactions, accelerants, retardants and consequences. This has improved our understanding of the long-term behaviour of reinforced concrete structures. However, the strengthening of reinforced concrete structures for durability has to date been mainly undertaken after expert assessment of field data followed by the development of a scheme to both terminate continuing degradation, by separating the structure from the environment, and strengthening the structure. The process does not include any significant consideration of the residual load-bearing capacity of the structure and the highly variable nature of estimates of such remaining capacity. Development of performance curves for deteriorating bridge structures has not been attempted due to the difficulty in developing a model when the input parameters have an extremely large variability. This paper presents a framework developed for an asset management system which assesses residual capacity and identifies the most appropriate rehabilitation method for a given reinforced concrete structure exposed to aggressive environments. In developing the framework, several industry consultation sessions have been conducted to identify input data required, research methodology and output knowledge base. Capturing expert opinion in a useable knowledge base requires development of a rule based formulation, which can subsequently be used to model the reliability of the performance curve of a reinforced concrete structure exposed to a given environment.