The safe insertion of peripheral intravenous catheters : a mixed methods descriptive study of the availability of the equipment needed

Background: Intravenous cannulation is undertaken in a high proportion of hospitalised patients. Much international attention has been given to the use of care bundles to reduce the incidence of infection in these patients. However, less attention has been given to the systems required to ensure availability of the equipment needed to support these care bundles. Our objectives were to assess how reliably the equipment recommended for a peripheral intravenous care bundle was available for use, and to explore factors which contributed to its non-availability. Methods: We studied 350 peripheral cannula insertions in three NHS hospital organisations across the UK. Staff inserting cannulae were asked to report details of all equipment problems. Key staff were then interviewed to identify the causes of problems with equipment availability, using semi-structured qualitative interviews and a standard coding frame. Results: 47 equipment problems were recorded during 46 of 350 cannulations, corresponding to a reliability of 87%, or 94% if problems with sharps disposal were excluded. Overall reliability was similar in all three organisations, but the types of problem varied. Interviews revealed a variety of causes including issues associated with purchasing policies, storage facilities, and lack of teamwork and communication in relation to reordering. The many human factors related to the supply chain were highlighted. Often staff had adopted work-arounds to deal with these problems. Conclusions: Overall, 87% of cannulations had the correct and functional equipment available. Different problems were identified in different organisations, suggesting that each had resolved some issues. Supply chain management principles may be useful to support best practice in care bundle delivery. Keywords: Cannulation, Patient safety, Equipment, Care bundles, Hospital acquired bacteraemia, Systems reliabilit

Using Bayesian Agents to Enable Distributed Network Knowledge: A Critique

Resource based theory (RBT) states that there are dynamic relationships between individual-resource interactions, which ultimately determine an organisation’s global behaviour in its environment. When combining in idiosyncratic, functional ways to enable an organisation’s global behaviour, we call them complementary resource combinations (CRCs), and socially complex resource combinations (SRCs) when referring to only the complex web of social interactions of these resources. Casual ambiguity refers to the inherent uncertainty when the global behaviour is both tangibly evident and known, but the way in which the unique local interactions between SRCs amongst themselves and the environment ultimately contribute to the global behaviour is often unclear. Thus, in order to understand social complexity and causal ambiguity of an organization, the SRCs emergent behaviours and the causal local interactions must be observed over time, and the inter-relationships must be identified and made tangible. In our research, we use simple agents to observe the local and global behaviours, to mine the inter-relationships and to model the SRCs. These agents are organized into two types of agencies: Bayesian agencies and competence agencies. The Bayesian agencies are the observers – they collectively implement specialised, distributed Bayesian networks, which enable the agencies to collectively mine relationships between emergent global behaviours and the local interactions that caused them to occur. The competence agencies are the actors – they use the beliefs of selected Bayesian agencies and perform dynamic network analysis. In dynamic network analysis, temporal data is used to predict changes that will occur in the SRCs. Most importantly, the Bayesian agencies observe and mine temporal patterns in various metrics over time, and the competence agencies evolve the SRCs. Relationships discovered and maintained by Bayesian agencies and competence agencies are integrated into cutting-edge, resource-based topic maps (ISO 13250:2002), which provide a way of modelling the SRCs

Chlorite and epidote mineral chemistry in porphyry ore systems: a case study of the Northparkes district, NSW, Australia

Propylitic alteration, characterized by the occurrence of chlorite and epidote, is typically the most extensive and peripheral alteration facies developed around porphyry ore deposits. However, exploration within this alteration domain is particularly challenging, commonly owing to weak or nonexistent whole-rock geochemical gradients and the fact that similar assemblages can be developed in other geologic settings, particularly during low-grade metamorphism. We document and interpret systematic spatial trends in the chemistry of chlorite and epidote from propylitic alteration around the E48 and E26 porphyry Cu-Au deposits of the Northparkes district, New South Wales, Australia. These trends vary as a function of both distance from hydrothermal centers and alteration paragenesis. The spatial trends identified in porphyry-related chlorite and epidote at Northparkes include (1) a deposit-proximal increase in Ti, As, Sb, and V in epidote and Ti in chlorite, (2) a deposit-distal increase in Co and Li in chlorite and Ba in epidote, and (3) a pronounced halo around deposits in which Mn and Zn in chlorite, as well as Mn, Zn, Pb, and Mg in epidote, are elevated. Chlorite Al/Si ratios and epidote Al/Fe ratios may show behavior similar to that of Mn-Zn or may simply decrease outward, and V and Ni concentrations in chlorite are lowest in the peak Mn-Zn zone. In comparison to porphyry-related samples, chlorite from the regional metamorphic assemblage in the district contains far higher concentrations of Li, Ca, Ba, Pb, and Cu but much less Ti. Similarly, metamorphic epidote contains higher concentrations of Sr, Pb, As, and Sb but less Bi and Ti. These chlorite and epidote compositional trends are the net result of fluid-mineral partitioning under variable physicochemical conditions within a porphyry magmatic-hydrothermal system. They are most easily explained by the contribution of spent magmatic-derived ore fluid(s) into the propylitic domain. It is envisaged that such fluids experience progressive cooling and reduction in fs2 during outward infiltration into surrounding country rocks, with their pH controlled by the extent of rock-buffering experienced along the fluid pathway

Physicochemical conditions of formation for bismuth mineralization hosted in a magmatic-hydrothermal breccia complex: an example from the Argentine Andes

The San Francisco de los Andes breccia-hosted deposit (Frontal Cordillera, Argentina) is characterized by complex Bi-Cu-Pb-Zn-Mo-As-Fe-Ag-Au mineralization. After magmatichydrothermal brecciation, tourmaline and quartz partially cemented open spaces, followed by quiescent periods where Bi-Cu-Pb-Zn ore formed. Bismuth ore precipitation is characterized by Bi-sulfides, sulfosalts, and tellurosulfide inclusions, which temporally co-exist with Ag-telluride inclusions and chalcopyrite. Three distinct Bi mineralizing stages have been defined based on the following mineral assemblages: (1) Bismuthinite (tetradymite–hessite inclusions); (2) Bismuthinite (tetradymite–hessite inclusions) + cosalite (tetradymite inclusions) + chalcopyrite; and (3) Cosalite (tetradymite inclusions) + chalcopyrite. Overall, Ag-poor bismuthinite hosts both Bi-tellurosulfide and Ag-telluride inclusions, whereas Ag-rich cosalite only hosts tetradymite inclusions.In this study, we discuss the effects of temperature, pressure, vapor saturation, salinity, acidity/alkalinity, and redox conditions on Bi-rich mineralizing fluids. Evolving hydrothermal fluid compositions are derived from detailed paragenetic, analytical, and previous fluid inclusion studies. Based on trace minerals that co-precipitated during Bi ore formation, mineral chemistry, and quartz geothermobarometry, a thermodynamic model for bismuth species was constructed. Sulfur and tellurium fugacities during Bi-ore precipitation were constrained for the three mineralizing stages at a constant pressure of 1 kbar under minimum and maximum temperatures of 230 and 400 °C, respectively. We infer that Te was transported preferentially in a volatile-rich phase. Given that Te solubility is expected to be low in chloride-rich hydrothermal fluids, telluride and tellurosulfide inclusions are interpreted to have condensed from magmatically-derived volatile tellurium (e.g., Te2(g) or H2Te(g)) into deep-seated, dense, metal-rich brines. Tellurium minerals in the hydrothermal breccia cement provide a direct genetic link with the underlying magmatic system. Though the vertical extent of the breccia complex is unknown, the abundance of Te-bearing minerals could potentially increase with depth and not only occur as small telluride inclusions in Bi-minerals. A vertical zoning of Te-minerals could prove to be important for exploration of similar magmatic-hydrothermal brecciapipes and/or dikes

Adaptive Bayesian agents: Enabling distributed social networks

This article brings together two views of organisations: resource-based theories (RBT) and social network analysis (SNA). Resource-based theories stress the importance of tangible assets, as well as less tangible ones, in the competitive advantage and success of organisations. However, they provide little insight into how resources are brought together by an organisation to generate core competencies that provide a source of differentiation that cannot easily be reproduced or substituted. In contrast SNA provides insight into the complexity of organisations and the interaction between the people within them, taking account of uncertainty and complexity. However, neither perspective gives significant insight into how organisations evolve over time, and how their competitive position is sustained or eroded. Our view is that integrating these two perspectives gives deeper insight into the basis of competitive advantage, and how it can evolve over time. ‘Complementary resource combinations’ (CRCs), bundles of related resources, can provide a basis for differentiation but only when these are embedded in a complex web of social interactions specific to the organisation. The ‘socially-complex resource combinations’ (SRCs) enable competitive advantage that is not readily reproduced or substituted, and which evolves over time in an uncertain and complex way. They are the basis of distinctive organisational competencies that enable the organisation to be a player in the marketplace, and in some cases to sustain competitive advantage. To understand how competitive advantage can be sustained, it is necessary to understand how these SRCs evolve over time, based on the interactions in social networks. To do this, we use Bayesian networks and topic maps, making hidden social relationships tangible. We use dynamic agents to observe local and global behaviours to model the SRCs. In this, we use the concept of ‘agencies’ that are networks of individual agents and which can solve problems and adapt in ways that are too complex for individual agents. The article outlines how this approach can be used to model complex social networks over time, recognising uncertainty and complexity, hence giving the ability to predict changes that will occur in the SRCs

Higher Water Loss on Earth-like Exoplanets in Eccentric Orbits

The climate of a terrestrial exoplanet is controlled by the type of host star, the orbital configuration and the characteristics of the atmosphere and the surface. Many rocky exoplanets have higher eccentricities than those in the Solar System, and about 18% of planets with masses 0.1. Underexplored are the implications of such high eccentricities on the atmosphere, climate, and potential habitability on such planets. We use WACCM6, a state-of-the-art fully-coupled Earth-system model, to simulate the climates of two Earth-like planets; one in a circular orbit (e = 0), and one in an eccentric orbit (e = 0.4) with the same mean insolation. We quantify the effects of eccentricity on the atmospheric water abundance and loss given the importance of liquid water for habitability. The asymmetric temperature response in the eccentric orbit results in a water vapour mixing ratio in the stratosphere (>20 ppmv) that is approximately five times greater than that for circular orbit (∼4 ppmv). This leads to at most ∼3 times increases in both the atmospheric hydrogen loss rate and the ocean loss rate compared with the circular case. Using the Planetary Spectrum Generator, we simulate the idealised transmission spectra for both cases. We find that the water absorption features are stronger at all wavelengths for the e = 0.4 spectrum than for the circular case. Hence, highly-eccentric Earth-like exoplanets may be prime targets for future transmission spectroscopy observations to confirm, or otherwise, the presence of atmospheric water vapour