Dynamic Actor Research Articles

Actin, gelsolin and filamin‐A are dynamic actors in the cytoskeleton remodelling contributing to the blood brain barrier phenotype

The brain vascular endothelium operates as a dynamic regulatory interface to maintain the cell environment of the nervous system. In the vicinity of astrocytes, brain endothelial cells develop characteristic features conferring a strong cellular impermeability which limits the penetration of various compounds. The aim of our study was to determine by differential proteomic analysis the changes occurring in bovine brain capillary endothelial cells (BBCEC) differentiated in co-culture with astrocytes compared with endothelial cells cultured alone. In order to obtain reproducible and meaningful protein profiles of in vitro blood-brain barrier models, three sample preparation procedures were carried out to provide the first 2-D comparative proteomic study of BBCEC. Our study highlights advantages and drawbacks of each procedure. The cellular proteins prepared from mechanical scraping of collagen-seeded BBCEC were strongly contaminated by serum proteins. Enzymatic dissociation of BBCEC by trypsin or collagenase solved this problem. A comparative 2-DE profile study of collagenase-harvested BBCEC revealed that cytoskeleton-related proteins (actin, gelsolin and filamin-A) show the most significant quantitative changes in the Triton soluble protein fraction from BBCEC that exhibit characteristics closest to the in vivo situation.

Actor modelling and its contribution to the development of integrative strategies for management of pharmaceuticals in drinking water

Widespread presence of human pharmaceuticals in water resources across the globe is documented. While some, but certainly not enough, research on the occurrence, fate and effect of pharmaceuticals in water resources has been carried out, a holistic risk management strategy is missing. The transdisciplinary research project “start” aimed to develop an integrative strategy by the participation of experts representing key actors in the problem field “pharmaceuticals in drinking water”. In this paper, we describe a novel modelling method, actor modelling with the semi-quantitative software DANA (Dynamic Actor Network Analysis), and its application in support of identifying an integrative risk management strategy. Based on the individual perceptions of different actors, the approach allows the identification of optimal strategies. Actors' perceptions were elicited by participatory model building and interviews, and were then modelled in perception graphs. Actor modelling indicated that an integrative strategy that targets environmentally-responsible prescription, therapy, and disposal of pharmaceuticals on one hand, and the development of environmentally-friendly pharmaceuticals on the other hand, will likely be most effective for reducing the occurrence of pharmaceuticals in drinking water (at least in Germany where the study was performed). However, unlike most other actors, the pharmaceutical industry itself does not perceive that the production of environmentally-friendly pharmaceuticals is an action that helps to achieve its goals, but contends that continued development of highly active pharmaceutical ingredients will help to reduce the occurrence of pharmaceuticals in the water cycle. Investment in advanced waste or drinking water treatment is opposed by both the wastewater treatment company and the drinking water supplier, and is not mentioned as appropriate by the other actors. According to our experience, actor modelling is a useful method to suggest effective and realisable integrative risk management strategies in complex problem fields that involve many societal actors.

Legalizing Prostitution: Morality Politics in Western Australia

There is now a sizeable literature examining moral panics and moral crusades in various societies, yet the literature is largely centred on the dynamics of panics and the social forces promoting them, while devoting almost no attention to the state. The state may play a key role in the process-either fanning or defusing popular alarm over a problem. In some panics, the state becomes an arena of struggle, or morality politics, between forces that promote and challenge claims regarding some social evil. The process of legislating morality provides a unique opportunity to examine the state as a dynamic actor in its own right. The article examines this in the context of the recent debate over legalizing prostitution in Western Australia.

Ecstasy in the city: Synthetic drug markets in Europe

How do “new” drug markets develop and operate? Which are the characteristics of synthetic drug suppliers? How are they organized, owned and managed? This article summarizes the outcomes of a cross-national study which investigated three urban synthetic drug markets at a different stage of development: Amsterdam, Barcelona and Turin. The study – the first of this type in Europe – outlines a composite picture which clearly indicates the presence of rather flexible and dynamic actors and a quasi “free” drug economy. Hence, the role played by more structured, mafia-type organizations, even in Italy, needs to be reconceived. The wide use of primary sources, altogether the adoption of qualitative interpretative tools, contributed to shed some light on a phenomenon which is still poorly investigated both at national and international levels.

Expanding horizons: Women’s voices in community-driven development in the Cameroon grasslands

Communities are increasingly becoming development spaces where members are dynamic actors in fashioning issues of common interest. This paper explores women’s efforts at building social capital for communitarian ventures in selected rural localities of the Cameroon grasslands. It is argued that effective participation in raising livelihoods and infrastructure provisioning is facilitated through women’s social networks (njangis). The paper situates the gender concerns in community participation, rekindled through village development associations (VDAs) – crucial in needs identification, prioritization and execution of identified projects. Based on focused field studies in selected localities, it is established that due to their low social status, workloads and tight schedule, women remain on the sidelines of the leadership in VDAs. However, women’s in-cash or in-kind contribution remains crucial to the successful implementation of projects. Enhancing female participation hinges on efforts at erasing cultural stereotypes that project women as domestic workers, improving literacy, increased access to productive resources especially land, direct support to women’s agricultural activity and improved rural infrastructure (roads, water supply, and electricity) that is compromising women’s participation and empowerment drive.

Ireland’s National Innovation System: An Exploratory Study of Supporting Institutions and Dynamic Actors

Abstract This paper begins with a brief look at the literature on national innovation systems (NIS). Building on the NIS approach, we present a simple conceptual framework. National innovative competence is dependent on the presence of dynamic STI actors, operating within the confines of compatible institutions. We distinguish the roles played by different STI actors and argue that heterogeneous actors engage in innovation for different reasons. Collaborative innovation is not always a natural consequence of engagement in innovation but is characterised by a distinct set of considerations. The latter part of the paper is concerned with the application of this conceptual framework to the case of Ireland. We identify the institutions pertaining to Ireland’s current innovative performance. An outline of STI actors according to their role in the system is then presented. In turn we outline the various contributions of Irish STI actors and explore their motives for engaging in innovation and collaborative innovation.

Dynamic actor network analysis for diffuse pollution in the province of North-Holland

Diffuse pollution problems involve numerous different organizations and this requires decision makers to involve different actors if they want to develop policies that have a chance of being implemented effectively. A first step in such interactive policy development would be to gain an overview of the different actors involved in diffuse pollution problems, as well as their views on the problem, their interests and their means to influence policy development and implementation. Dynamic Actor Network Analysis (DANA) offers a method that helps analysts in providing such an overview, and the use of this method is explored through its application to a case in the Dutch province of North Holland. The described case specifically focuses on the use of herbicides in public space and involves actors from regional water management authorities, municipalities and private sector users. An important finding is that there is an imbalance in the perceptions of actors that needs to be addressed by water management authorities. The paper concludes that DANA is a promising tool for offering new and useful insights to decision makers, although more practical experience is needed to better assess the utility of this analysis tool.

SMC proteins at the crossroads of diverse chromosomal processes.

How should a protein be designed to serve in processes as diverse as chromosome condensation, sister chromatid cohesion, DNA recombination, gene dosage regulation, and perhaps even gene silencing or transcriptional regulation--which occur in both mitosis and meiosis? Such a protein or protein complex needs to bear DNA interaction domains, it needs the capacity to use energy to move DNA, it needs to enter into highly specific protein interactions, it needs to be large enough to link two DNA molecules, it needs to be of sufficient flexibility to cope with different types of chromatin structure, yet it also needs to be rigid enough to pull, push or enclose DNA. SMC proteins fulfill these requirements and form the core units of high molecular weight complexes that act in all those processes, and are essential for some of them. SMC stands for 'Structural Maintenance of Chromosomes', although SMC proteins are not static scaffold proteins merely providing support for a particular chromosome structure. SMC proteins are rather highly dynamic actors, that generate and modulate chromosome structures, affecting a plethora of biological processes.

Student placements in the nursing home setting

IN 1999, one of the UK government’s responses to the shortage of qualified nurses was to significantly increase the number of student nurses (DoH 1999). This led to an increase in demand for clinical placements, at a time when the nature of care in the trust hospitals was becoming increasingly acute and short-stay. Qualified nurses, already in short supply, were under pressure from staff shortages and the push to reduce waiting lists, demanding a rapid throughput of patients. This situation was not conducive to the support of student nurses, particularly at the beginning of their pre-registration programme, when time and the reiteration of first principles in practice are required. Changing demographics have resulted in older people becoming the most frequent users of healthcare facilities (DoH 2000). In 1999, not all students at the Institute of Health and Community Studies at Bournemouth University (IHCS) had the opportunity to develop specific skills and knowledge in relation to the care of this increasingly large client group. Students often have negative attitudes towards older people adding disinclination to lack of opportunity (Hinchliffe 1980, Roberts and Powell 1978). The media portrayal of the nurse is generally of a dynamic actor in an acute setting where technical skills are paramount. Images of nurses caring for older people in a long-term setting, where nursing problems might be complex and change is slow, are rarely used. This has been emphasised by Nazarko (1999), who pointed out that nurses believe that nursing care of older people is ‘basic care’ with no specialist skills required. Experience has shown that although older people can be found in any hospital’s acute wards, skilled nursing is best practised in longstay residential nursing homes. Nursing homes also provide care for terminally ill people, respite care and care for the younger physically disabled and those who need rehabilitation. In such settings, the students’ understanding of older people as individuals with feelings and needs can be enhanced, and there is a more supportive environment with fewer pressures on staff. There is time to build relationships through which evaluative skills can develop. For these reasons, nursing home placements for first-year nursing students provide an ideal basis for developing their fundamental skills. Sheffer’s (1998) study conducted with first-year baccalaureate students in the US was convincing in its assertion that, due to the high acuity level of hospitalised clients, clinical placements for beginning students should continue to be with older patients in a nursing home setting. This study also showed that positive attitudes to older people occur as a result of this type of clinical experience. Similarly, Fuggle (1999), in a study of IHCS students after one year in a nursing home placement, found that ‘the perceived benefits of the placement... were the development of their basic nursing skills giving them a broad base upon which to build future skills’.

ALBA

In this paper, ALBA, A parallel Language Based on Actors, is introduced. ALBA [15] is a new programming language designed to take advantage of highly parallel architectures that use message passing as the fundamental low-level interaction primitive. ALBA is being developed as implementation language for the QUATRO parallel Database machine [5] in order to facilitate its portability and permit a homogeneous description of the QUATRO system to every multiprocessor machine.ALBA is a strong-typed language, and is oriented towards the development of both parallel and distributed applications. The actor paradigm in ALBA presents new characteristics such as the use of broadcast methods; dynamic actor allocations permitting the programmer to distribute actors on the machine, in a load-balancing way, on both a specific set of virtual processors or on all of the processors of the machine; different communication and synchronization mechanisms among actors, and others that are presented in this papcr.The ALBA programming language and the QUATRO Database Machine are being developed under the HELIOS operating system for a transputer machine.

A Model of the Informal Sector in Development

In discussions of economic development, industrial dualism is often ignored. Industry, or the modern sector, in developing countries is composed of an overregulated formal sector and a free‐entry informal sector. Because of the nature of the regulations we can, in general, identify the formal sector with large industry and the informal sector with small industry. The informal modern sector is often a dynamic actor in the process of economic development, frequently outpacing the growth of the formal modern sector. We investigate in a general equilibrium model the conditions under which the informal sector increases its capital stock more rapidly than the formal sector. We also look at the employment‐unemployment effects of industrial dualism.

OBSERVER ATTRIBUTION: EFFECTS OF DYNAMIC QUALITIES OF THE ACTOR

Research has shown that observers tend to attribute causality for an actor's behavior to dispositional characteristics of the actor rather than to external factors. Several authors have suggested that this phenomenon occurs because observers tend to focus attention on the actor. The present experiment was designed to determine whether dynamic qualities of the actor can, in part, account for observers' attentional and attributional behavior. Subjects were assigned the role of observers and were exposed to either a mildly dynamic or a stable actor. Subjects' attributions for the actor's behavior revealed that greater causality was attributed to the dynamic actor.