32 research outputs found

    Design and fabrication of gas cell targets for laboratory astrophysics experiments on the Orion high-power laser facility

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    This paper describes the design and fabrication of a range of ‘gas cell’ microtargets produced by the Target Fabrication Group in the Central Laser Facility (CLF) for academic access experiments on the Orion laser facility at the Atomic Weapons Establishment (AWE). The experiments were carried out by an academic consortium led by Imperial College London. The underlying target methodology was an evolution of a range of targets used for experiments on radiative shocks and involved the fabrication of a precision machined cell containing a number of apertures for interaction foils or diagnostic windows. The interior of the cell was gas-filled before laser irradiation. This paper details the assembly processes, thin film requirements and micro-machining processes needed to produce the targets. Also described is the implementation of a gas-fill system to produce targets that are filled to a pressure of 0.1–1 bar. The paper discusses the challenges that are posed by such a target

    The global abundance of tree palms

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    Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≄10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

    A taxonomic backbone for the global synthesis of species diversity in the angiosperm order Caryophyllales

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    The Caryophyllales constitute a major lineage of flowering plants with approximately 12500 species in 39 families. A taxonomic backbone at the genus level is provided that reflects the current state of knowledge and accepts 749 genera for the order. A detailed review of the literature of the past two decades shows that enormous progress has been made in understanding overall phylogenetic relationships in Caryophyllales. The process of re-circumscribing families in order to be monophyletic appears to be largely complete and has led to the recognition of eight new families (Anacampserotaceae, Kewaceae, Limeaceae, Lophiocarpaceae, Macarthuriaceae, Microteaceae, Montiaceae and Talinaceae), while the phylogenetic evaluation of generic concepts is still well underway. As a result of this, the number of genera has increased by more than ten percent in comparison to the last complete treatments in the Families and genera of vascular plants” series. A checklist with all currently accepted genus names in Caryophyllales, as well as nomenclatural references, type names and synonymy is presented. Notes indicate how extensively the respective genera have been studied in a phylogenetic context. The most diverse families at the generic level are Cactaceae and Aizoaceae, but 28 families comprise only one to six genera. This synopsis represents a first step towards the aim of creating a global synthesis of the species diversity in the angiosperm order Caryophyllales integrating the work of numerous specialists around the world

    The LHCb upgrade I

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    The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software

    Jamestown Canyon virus encephalitis in a heart transplant patient

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    Jamestown Canyon virus (JtCV) is an arbovirus and a member of the California serogroup. To our knowledge, all the cases of JtCV have been reported in immunocompetent patients since it was first detected in 1997. We report a case of JtCV encephalitis in a solid organ transplant patient. A 48-year-old woman from Wisconsin had multiple hospital admissions for symptoms of progressive confusion, visual hallucinations, and inability to perform self-care. Initial evaluation was significant for lymphocytes in cerebrospinal fluid (CSF), and multiple infectious and metabolic causes were excluded. Further investigation found JtCV IgM in serum, and CSF. The patient\u27s clinical course was compatible with JtCV encephalitis, and she was treated with ribavirin in addition to reduction of her immunosuppressive medications. She showed gradual and significant improvement in her mental and functional status. JtCV can cause a variety of symptoms that range from a flu-like syndrome to encephalitis. There have been an increased number of reported cases in recent years which is attributed to increased physician awareness and the availability of laboratory testing. Optimal treatment is still not known

    Examining the relationship between vancomycin area under the concentration time curve and serum trough levels in adults with presumed or documented staphylococcal infections

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    BACKGROUND: Investigations of the relationship between vancomycin trough concentrations and area under the concentration time curve (AUC) are growing but still limited. The authors sought to determine vancomycin exposure among hospitalized adults with presumed or confirmed invasive staphylococcal infections using two-level pharmacokinetic monitoring in order to inform changes to an institutional vancomycin dosing protocol. METHODS: This was a retrospective observational study performed in two acute care hospitals. Adults prescribed vancomycin (therapeutic trough 15-20mg/L) for a presumed or documented invasive staphylococcal infection were evaluated. Two steady-state serum vancomycin levels were used to determine each patient\u27s 24-hour AUC to MIC ratio (AUC/MIC) using a non-Bayesian, equation-based approach. Patient demographics and crude clinical outcomes were also collected. RESULTS: Thirty-four patients were included in the study, with two patients having vancomycin levels drawn twice (36 sets of levels). Most patients were located in an intensive care unit (91.2%) and 85.3% of patients were prescribed vancomycin for bacteremia, pneumonia, or endocarditis. The mean ± standard deviation vancomycin Cmin was 16.6 ± 6.1mg/L and the mean AUC/MIC was 588 ± 156mg/L*hr. The rate of 24-hour vancomycin AUC/MIC target attainment was 91.2% (n=31/34). Of the patients with a Cmin \u3e 9mg/L, 100%(n=33) achieved AUC /MICvalues \u3e400mg/L*hr and 93.9% were \u3e 500mg/L*hr. There was a strong correlation between vancomycin Cmin and AUC24hr (R=0.731; p\u3c0.001). CONCLUSIONS: Targeting a vancomycin trough between 15 and 20 mg/L frequently resulted in an AUC/MIC greater than thought to be necessary for efficacy optimization. Considering these findings alongside the practical challenges associated with wide-scale implementation of AUC monitoring, reducing the target trough as a means to prevent vancomycin overexposure warrants clinical consideration and further evaluation

    Risk assessment for infected endocarditis in Staphylococcus aureus bacteremia patients: when is transesophageal echocardiography needed?

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    AIMS: Echocardiography is the main technique for the diagnosis of endocarditis in patients with METHODS AND RESULTS: Data from SAB patients admitted from 2012 to 2014 were collected. We tested the Palraj scores to stratify patients\u27 risk for endocarditis. Moreover, we analyzed our population to identify any other possible clinical predictors of endocarditis not included in the score. Endocarditis was diagnosed in 38 of 205 patients (18.5%). Palraj\u27s score was effective in the detection of patients at high risk of endocarditis. In addition, we identified the presence of cardiac devices, prolonged bacteremia and intravenous drug abuse (IVDA) as elements strongly correlated with endocarditis. Two scoring systems (Day-1 and Day-5) were derived including IVDA as a variable. Using a Day-1 cut-off value ≄5 and a Day-5 cut-off value ≄2, the \u27modified Palraj\u27s score\u27 showed sensitivities of 42.1% and 97.0% and specificities of 88.6% and 32.0% for Day-1 and Day-5 scores, respectively. CONCLUSION: We modify and expand upon an effective scoring system to identify SAB patients at high risk for endocarditis in order to guide use of TEE. The inclusion of IVDA in the criteria for the calculation of the scores improves its effectiveness

    Penicillin-Resistant

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    Impact of a systematic pharmacist-initiated antibiotic time-out intervention for hospitalized adults

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    INTRODUCTION: Antibiotic time-outs (ATO) are a recommended antimicrobial stewardship action, but data assessing their impact are lacking. This study investigated the impact of a systematic, pharmacist initiated ATO intervention. METHODS: This pre-post study included inpatients on hospitalist and intensivist services receiving empiric antibiotics for ≄48 hours. The ATO was initiated by pharmacists after 48 hours of empiric therapy and the outcome was documented including antibiotic indication, plan, and duration. An electronic medical record (EMR) alert facilitated ATO completion and pharmacists and prescribers received education prior to implementation. The primary outcome was EMR documentation of an antibiotic plan by 72 hours. Secondary outcomes included antibiotic utilization and antibiotic therapy modifications by 2 hours. RESULTS: 399 patients were included, 199 pre- and 200 post-intervention. The most common indications were pneumonia (32%), intra-abdominal infection (20%) and urinary tract infection (19%), with no between-group differences. EMR documentation of an antibiotic plan significantly improved in the post-intervention group (19% vs. 79%, p\u3c0.0001) as did modifications to antibiotic therapy. The median duration of in-hospital antibiotic therapy was similar between groups (4.0 vs. 4.0 days, p = 0.2499). Approximately 45% of patients in each group received discharge antibiotics and median duration of discharge antibiotic therapy prescribed was reduced (7 vs. 5 days in the pre- and post-intervention groups, respectively; p = 0.0140). DISCUSSION: Implementation of pharmacist initiated ATO was associated with improvements in supporting EMR documentation and antibiotic therapy modifications. These findings highlight an important role in which pharmacists can serve as part of a collaborative antibiotic stewardship team
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