14 research outputs found

    Strong electronic correlations in superconducting organic charge transfer salts

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    We review the role of strong electronic correlations in quasi--two-dimensional organic charge transfer salts such as (BEDT-TTF)2X_2X, (BETS)2Y_2Y and ÎČâ€Č\beta'-[Pd(dmit)2_2]2Z_2Z. We begin by defining minimal models for these materials. It is necessary to identify two classes of material: the first class is strongly dimerised and is described by a half-filled Hubbard model; the second class is not strongly dimerised and is described by a quarter filled extended Hubbard model. We argue that these models capture the essential physics of these materials. We explore the phase diagram of the half-filled quasi--two-dimensional organic charge transfer salts, focusing on the metallic and superconducting phases. We review work showing that the metallic phase, which has both Fermi liquid and `bad metal' regimes, is described both quantitatively and qualitatively by dynamical mean field theory (DMFT). The phenomenology of the superconducting state is still a matter of contention. We critically review the experimental situation, focusing on the key experimental results that may distinguish between rival theories of superconductivity, particularly probes of the pairing symmetry and measurements of the superfluid stiffness. We then discuss some strongly correlated theories of superconductivity, in particular, the resonating valence bond (RVB) theory of superconductivity. We conclude by discussing some of the major challenges currently facing the field.Comment: A review: 52 pages; 10 fig

    Therapeutic drug monitoring when using cefepime in continuous renal replacement therapy: seizures associated with cefepime

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    Ensuring effective, safe drug dosing in critically ill patients can be difficult, due to variable and dynamic organ function

    GLAMS: A graphical method for capturing land and water management practices in agroecosystems

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    Modification of native ecosystems through land use can affect the biophysical functioning of agroecosystems, with spatial arrangement (configuration) through time often determining the degree to which landscapes experience dysfunctional states. An improved understanding is needed of how spatial and temporal patterns in land use affect ecohydrological dysfunctions, such as how landscapes leak or fail to retain water and soil, at scales relevant to farm management. We develop and apply a Graphical LAndscape Map Survey method, or "GLAMS", for measuring changes in landscape function based upon a 3D graphic of a hypothetical sub-catchment. GLAMS was applied within four Landcare Groups comprised of farmers from the Western Catchments of Southeast Queensland, Australia. The aim was to capture the behaviors of farmers who manage land use under natural variations in precipitation, especially extended dry periods, and with the associated risks from ecohydrologically dysfunctional or 'leaky' landscapes. GLAMS provided variable spatial and temporal resolution which allowed quantification of the land use responses for three different property sizes: (1) small, less than 100 ha; (2) medium, 100-500 ha; and (3) large, larger than 500 ha. Responses were quantified using Bayesian Belief Networks to provide probability estimates of the likelihood of a given action, taking place within a particular part of the landscape, considering both climatic and ecohydrological risks. The findings indicated that GLAMS was more intuitive to farmers than traditional question-based surveys, resulting in a low cost technique that is rapid to implement while providing spatially explicit information relevant to farm and catchment management

    Determinants of procedural pain intensity in the intensive care unit: the EuropainÂź study

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    Rationale:Intensive care unit (ICU) patients undergo several diagnostic and therapeutic procedures every day. The prevalence, intensity, and risk factors of pain related to these procedures are not well known. Objectives: To assess self-reported procedural pain intensity versus baseline pain, examine pain intensity differences across procedures, and identify risk factors for procedural pain intensity. Methods: Prospective, cross-sectional, multicenter, multinational study of pain intensity associated with 12 procedures. Data were obtained from 3,851 patients who underwent 4,812 procedures in 192 ICUs in 28 countries. Measurements andMain Results: Painintensity on a 0–10 numeric rating scale increased significantly from baseline pain during all procedures (P , 0.001). Chest tube removal, wound drain removal, and arterial line insertion were the three most painful procedures, with median pain scores of 5 (3–7), 4.5 (2–7), and 4 (2–6), respectively. By multivariate analysis, risk factors independently associated with greater procedural pain intensity were the specific procedure; opioid administration specifically for the procedure; preprocedural pain intensity; preprocedural pain distress; intensity of the worst pain on the same day, before the procedure; and procedure not performed by a nurse. A significant ICU effect was observed, with no visible effect of country because of its absorption by the ICU effect. Some of the risk factors became nonsignificant when each procedure was examined separately. Conclusions: Knowledge of risk factors for greater procedural pain intensity identified in this study may help clinicians select interventions that are needed to minimize procedural pain. Clinical trial registered with www.clinicaltrials.gov (NCT 01070082)

    Postoperative critical care and high-acuity care provision in the United Kingdom, Australia, and New Zealand

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    BACKGROUND: Decisions to admit high-risk postoperative patients to critical care may be affected by resource availability. We aimed to quantify adult ICU/high-dependency unit (ICU/HDU) capacity in hospitals from the UK, Australia, and New Zealand (NZ), and to identify and describe additional 'high-acuity' beds capable of managing high-risk patients outside the ICU/HDU environment. METHODS: We used a modified Delphi consensus method to design a survey that was disseminated via investigator networks in the UK, Australia, and NZ. Hospital- and ward-level data were collected, including bed numbers, tertiary services offered, presence of an emergency department, ward staffing levels, and the availability of critical care facilities. RESULTS: We received responses from 257 UK (response rate: 97.7%), 35 Australian (response rate: 32.7%), and 17 NZ (response rate: 94.4%) hospitals (total 309). Of these hospitals, 91.6% reported on-site ICU or HDU facilities. UK hospitals reported fewer critical care beds per 100 hospital beds (median=2.7) compared with Australia (median=3.7) and NZ (median=3.5). Additionally, 31.1% of hospitals reported having high-acuity beds to which high-risk patients were admitted for postoperative management, in addition to standard ICU/HDU facilities. The estimated numbers of critical care beds per 100 000 population were 9.3, 14.1, and 9.1 in the UK, Australia, and NZ, respectively. The estimated per capita high-acuity bed capacities per 100 000 population were 1.2, 3.8, and 6.4 in the UK, Australia, and NZ, respectively. CONCLUSIONS: Postoperative critical care resources differ in the UK, Australia, and NZ. High-acuity beds may have developed to augment the capacity to deliver postoperative critical care
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