785 research outputs found
Complex Systems Science: Dreams of Universality, Reality of Interdisciplinarity
Using a large database (~ 215 000 records) of relevant articles, we
empirically study the "complex systems" field and its claims to find universal
principles applying to systems in general. The study of references shared by
the papers allows us to obtain a global point of view on the structure of this
highly interdisciplinary field. We show that its overall coherence does not
arise from a universal theory but instead from computational techniques and
fruitful adaptations of the idea of self-organization to specific systems. We
also find that communication between different disciplines goes through
specific "trading zones", ie sub-communities that create an interface around
specific tools (a DNA microchip) or concepts (a network).Comment: Journal of the American Society for Information Science and
Technology (2012) 10.1002/asi.2264
A field study of team working in a new human supervisory control system
This paper presents a case study of an investigation into team behaviour in an energy distribution company. The main aim was to investigate the impact of major changes in the company on system performance, comprising human and technical elements. A socio-technical systems approach was adopted. There were main differences between the teams investigated in the study: the time of year each control room was studied (i.e. summer or winter),the stage of development each team was in (i.e. 10 months), and the team structure (i.e. hierarchical or heterarchical). In all other respects the control rooms were the same: employing the same technology and within the same organization. The main findings were: the teams studied in the winter months were engaged in more `planningâ and `awarenessâ type of activities than those studies in the summer months. Newer teams seem to be engaged in more sharing of information than older teams, which maybe indicative of the development process. One of the hierarchical teams was engaged in more `system-drivenâ activities than the heterarchical team studied at the same time of year. Finally, in general, the heterarchical team perceived a greater degree of team working culture than its hierarchical counterparts. This applied research project confirms findings from laboratory research and emphasizes the importance of involving ergonomics in the design of team working in human supervisory control
Compensatory Growth of the Sandbar Shark in the Western North Atlantic Including the Gulf of Mexico
The number of Sandbar Sharks Carcharhinus plumbeus in the western North Atlantic Ocean has experienced a drastic decline since the early 1980s, reaching a minimum during the early 1990s. Catch rates in the early 1990s were a mere 25% of those during the 1980s. According to several fishery-independent surveys, the low point in Sandbar Shark abundance followed a period of high exploitation. Growth models fit to age-length data collected from 1980 to 1983 and from 2001 to 2004 were compared to investigate potential changes in parameter estimates that might reveal compensatory responses in the Sandbar Shark population. Statistical differences were found between the model parameters for the two time periods, but the differences in growth rates were minimal. The parameters from the three-parameter von Bertalanffy growth model for female sharks during the 1980-1983 and 2000-2004 time periods were as follows: L = 188.4 and 178.3cm FL; k = 0.084 and 0.106; and t(0) = -4.097 and -3.41. For males the growth parameters were as follows: L = 164.63 and 173.66cm; k = 0.11 and 0.11; and t(0) = -3.62 and -3.33. The estimated age at 50% maturity for female Sandbar Sharks changed from 15years to 12.49years between the two time periods
PROTOCOL: Effectiveness of interpersonal psychotherapy in comparison to other psychological and pharmacological interventions for reducing depressive symptoms in women diagnosed with postpartum depression in low and middleâincome countries: A systematic review
Postpartum Depression (PPD) is highly prevalent among women in low and middle income countries (LMICs). World Heath Organization has recognised interpersonal Psychotherapy (IPT) as the first line treatment for the postpartum depression. The primary aim of this review is to evaluate the effectiveness of IPT alone or in combination with pharmacotherapy or other psychosocial therapies for treating depressive symptoms in women with postpartum depression. The generated evidence from this review will help to inform policies in relation to the treatment of postpartum depression in LMICs
A holistic multi-methodology for sustainable renovation
A review of the barriers for building renovation has revealed a lack of methodologies, which can promote sustainability objectives and assist various stakeholders during the design stage of building renovation/retrofitting projects. The purpose of this paper is to develop a Holistic Multi-methodology for Sustainable Renovation, which aims to deal with complexity of renovation projects. It provides a framework through which to involve the different stakeholders in the design process to improve group learning and group decision-making, and hence make the building renovation design process more robust and efficient. Therefore, the paper discusses the essence of multifaceted barriers in building renovation regarding cultural changes and technological/physical changes. The outcome is a proposal for a multi-methodology framework, which is developed by introducing, evaluating and mixing methods from Soft Systems Methodologies (SSM) with Multiple Criteria Decision Making (MCDM). The potential of applying the proposed methodology in renovation projects is demonstrated through a case study
Collective Impact Partnership and Backbone Organizations as Enablers of Childrenâs Well-Being
In this article, the question of partnership is approached from a perspective centred around the creation of a common agenda based on trust and from the childrenÂŽs point of view. Partnership and collaboration have traditionally been viewed as mechanisms to create bridges between organisations and institutions from the private, public and non-governmental sectors in order to enhance funder collaboratives, public-private partnerships, multi-stakeholder initiatives, social sector networks and collective impact initiatives. It was not however until Kania and KramerÂŽs (2011) seminal work on collective impact when this subject came to be viewed as a developmental process aiming at the creation of a common agenda and mutually agreed activities and consisting of five integral parts: a common agenda, shared measurement systems, mutually reinforcing activities, continuous communication and backbone support organisations. This article, based on a systematic review of the topic, maintains that partnership â approached from the point of view of children and through the lens of collective impact â constitutes a crucial mechanism in the creation of safe and comprehensive wellbeing for children. Thus, this article â using Kania and KramerÂŽs (2011) definition of collective impact and focusing on the structure of partnerships and the nature of trust in organisations as the prerequisite for partnership â advocates the importance of the UN SDG17 principle as the bringer of inclusive society built upon principles and values, a shared vision, and shared goals that place people at the centre of human endeavour.© Springer Nature Switzerland AG 2020. This is a post-peer-review, pre-copyedit version of an article published in Partnerships for the Goals. Encyclopedia of the UN Sustainable Development Goals. The final authenticated version is available online at: http://dx.doi.org/10.1007/978-3-319-71067-9_111-1.fi=vertaisarvioitu|en=peerReviewed
Growth, Fecundity, and Diets of Newly Established Silver Carp in the Middle Mississippi River
The silver carp Hypophthalmichthys molitrix has spread throughout the Mississippi River drainage. During 2003, we determined its population status and potential impact in the middle Mississippi River (MMR), the conduit between the lower Mississippi River and the upper Mississippi, Missouri, and Illinois rivers. We quantified growth, age structure, fecundity, and diets of silver carp sampled with trammel nets and AC electrofishing in main-channel areas. Mean length at age in the MMR exceeded that of populations in Asia by as much as 26%. Individuals were typically more than 1 year old and 230 mm total length, suggesting that small, young fish were absent. Individuals in this population matured earlier (age 2) than in the species\u27 native range. Regardless of phytoplankton variation (using chlorophyll a as a surrogate) and zooplankton concentration at MMR sites, phytoplankton was consistently most abundant in diets. Silver carp are finding suitable resources within the MMR, allowing individuals to grow rapidly during early life, persist as adults, and successfully disperse upstream
Learning capability : the effect of existing knowledge on learning
It has been observed that different people learn the same things in different ways - increasing their knowledge of the subject/domain uniquely. One plausible reason for this disparity in learning is the difference in the existing personal knowledge held in the particular area in which the knowledge increase happens. To understand this further, in this paper knowledge is modelled as a 'system of cognitive schemata', and knowledge increase as a process in this system; the effect of existing personal knowledge on knowledge increase is 'the Learning Capability'. Learning Capability is obtained in form of a function; although it is merely a representation making use of mathematical symbolism, not a calculable entity. The examination of the function tells us about the nature of learning capability. However, existing knowledge is only one factor affecting knowledge increase and thus one component of a more general model, which might additionally include talent, learning willingness, and attention
Influence of Statistical Estimators of Mutual Information and Data Heterogeneity on the Inference of Gene Regulatory Networks
The inference of gene regulatory networks from gene expression data is a difficult problem because the performance of the inference algorithms depends on a multitude of different factors. In this paper we study two of these. First, we investigate the influence of discrete mutual information (MI) estimators on the global and local network inference performance of the C3NET algorithm. More precisely, we study different MI estimators (Empirical, Miller-Madow, Shrink and SchĂŒrmann-Grassberger) in combination with discretization methods (equal frequency, equal width and global equal width discretization). We observe the best global and local inference performance of C3NET for the Miller-Madow estimator with an equal width discretization. Second, our numerical analysis can be considered as a systems approach because we simulate gene expression data from an underlying gene regulatory network, instead of making a distributional assumption to sample thereof. We demonstrate that despite the popularity of the latter approach, which is the traditional way of studying MI estimators, this is in fact not supported by simulated and biological expression data because of their heterogeneity. Hence, our study provides guidance for an efficient design of a simulation study in the context of network inference, supporting a systems approach
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