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Theories of perceptual decision making have been dominated by the idea that evidence accumulates in favor of different alternatives until some fixed threshold amount is reached, which triggers a decision. Recent theories have suggested that these thresholds may not be fixed during each decision but change as time passes. These collapsing thresholds can improve performance in particular decision environments, but reviews of data from typical decision-making paradigms have failed to support collapsing thresholds. We designed three experiments to test collapsing threshold assumptions in decision environments specifically tailored to make them optimal. An emphasis on decision speed encouraged the adoption of collapsing thresholds--most strongly through the use of response deadlines but also through instruction to a lesser extent--but setting an explicit goal of reward rate optimality through both instructions and task design did not. Our results suggest that collapsing thresholds models of decision-making are inconsistent with human behaviour even in some situations where there are normative motivations for these models.

Background Staphylococcus aureus bacteremia (SAB) is a clinically heterogeneous disease. The ability to identify subgroups of patients with shared traits (subphenotypes) is an unmet need to allow patient stratification for clinical management and research. We aimed to test the hypothesis that clinically relevant subphenotypes can be reproducibly identified among patients with SAB. Methods We studied 3 cohorts of adults with monomicrobial SAB: a UK retrospective observational study (Edinburgh cohort, n = 458), the UK ARREST trial (n = 758), and the Spanish SAFO trial (n = 214). Latent class analysis was used to identify subphenotypes using routinely collected clinical data without considering outcomes. Mortality and microbiologic outcomes were then compared between subphenotypes. Results Included patients had predominantly methicillin-susceptible SAB (1366 of 1430, 95.5%). We identified 5 distinct, reproducible clinical subphenotypes: (A) SAB associated with older age and comorbidity, (B) nosocomial intravenous catheter-associated SAB in younger people without comorbidity, (C) community-acquired metastatic SAB, (D) SAB associated with chronic kidney disease, and (E) SAB associated with injection drug use. Survival and microbiologic outcomes differed between the subphenotypes. Mortality was highest in subphenotype A and lowest in subphenotypes B and E. Microbiologic outcomes were worse in subphenotype C. In a secondary analysis of the ARREST trial, adjunctive rifampicin was associated with increased mortality in subphenotype B and improved microbiologic outcomes in subphenotype C. Conclusions We have identified reproducible and clinically relevant subphenotypes within SAB and provide proof of principle of differential treatment effects. Through clinical trial enrichment and patient stratification, these subphenotypes could contribute to a personalized medicine approach to SAB. [ABSTRACT FROM AUTHOR]

Abstract Climate change is predicted to affect species in aquatic ecosystems. In Africa, factors that may influence the responses of aquatic species are poorly studied and challenging to predict. In this study, we examined the potential distribution of three aquatic fern species in the genus Azolla in Africa under projected climate change scenarios. MaxEnt was used to create ecological niche models of the three species using occurrence data and environmental variables. All models had satisfactory AUC and TSS values, indicating high prediction precision (AUC and TSS > 0.801). Results showed that elevation and precipitation were the most important variables limiting the species' expansion in the future. In addition, we observed significant variations in the climatic niches of the three species and their distinct climatically appropriate regions. The current potential distribution ranges for the species varied between 2,328,726 km2 and 4,026,363 km2. According to the model predictions for the current period, the potential range of Azolla species extended outside the known and recorded locations; however, under future climate conditions, the species were projected to lose between 8.1% and 48% of their suitable habitats due to climate change. Our findings can be used to develop sustainable conservation measures for aquatic species and raise awareness about the effects of climate change.

TBM is the most severe form of tuberculosis. Clinical trial data are required to provide an evidence base for adjunctive dexamethasone in HIV-positive individuals with TBM, and to guide clinical practice. This document details the planned analyses at 12 months post randomisation for the ACT HIV clinical trial (NCT03092817); ‘a randomised double-blind placebo-controlled trial of adjunctive dexamethasone for the treatment of HIV co-infected adults with tuberculous meningitis (TBM)’. The primary endpoint of the ACT HIV trial is death (from any cause) over the first 12 months after randomisation. This statistical analysis plan expands upon and updates the analysis plan outlined in the published study protocol.

Tuberculous meningitis (TBM) is the most severe form of tuberculous with substantial mortality. In May 2015, 54 researchers from 10 countries met in Da Lat, Vietnam, to discuss advances in TBM. Among the attendees were researchers involved in pivotal studies on the use of Xpert MTB/Rif for TBM diagnosis. Attendees discussed the 2014 World Health Organization strong recommendation favoring the use of Xpert "in preference to conventional microscopy and culture as the initial diagnostic test for cerebrospinal fluid (CSF) if the sample volume is low or if additional specimens cannot be obtained to make a quick diagnosis." Attendees were concerned that the limitations of Xpert testing for TBM are not emphasized. Clear guidance is needed for the investigational pathway for TBM, including recommendations on the diagnostic package of investigations, which does not stop with Xpert testing. Second, emphasis on the large CSF volumes (ideally 8-10 mL) needed for Xpert testing is required. Guidelines should also emphasize that TBM is a medical emergency and early treatment reduces mortality.

Hao Chung The et al. analyze 1,804 Shigella genome sequences from organisms isolated in four Southeast Asian countries over three decades to study the evolution of both S. flexneri and S. sonnei. This study suggests that adaptation to antimicrobial pressure may have played a pivotal role in the recent evolutionary trajectory of Shigella in Southeast Asia.

Hydrostachys flabellifera, a new species of Hydrostachyaceae found in a stream in Manandriana, Madagascar, is described and illustrated herein. It is similar to H. verruculosa and H. laciniata in morphology, but can be distinguished from them by its leaves with sparsely arranged, flabelliform and palmately parted emergences, obvious rachis and the pattern of segments arranged on the male bracts. Molecular phylogenetic analysis of the nuclear ribosomal internal transcribed spacer (ITS) dataset provides a robust support for it as a new species as well.

Abstract Background Isolated persistent left superior vena cava (PLSVC) is a rare vascular anatomic variant, which can be an incidental finding at the time of an endovascular procedure. Case presentation This report describes the technical success, adverse events, and clinical outcomes of transjugular intrahepatic portosystemic shunt (TIPS) creation via isolated PLSVC. Three adult patients with cirrhosis and isolated PLSVC underwent TIPS placement successfully with one major adverse event. Two patients required TIPS revision within 90 days. There were no deaths within 90 days. Conclusions TIPS creation via isolated PLSVC is feasible using standard techniques with a left jugular vein approach. Caution is warranted during the procedure to assess for any aberrant drainage pattern to the left atrium and to prepare for potentially challenging instrument navigation through the coronary sinus.

Abstract Purpose To quantify and categorize fluoroscopically-guided procedures with radiation doses exceeding 5000 mGy reference point air kerma (Ka,r). Ka,r > 5000 mGy has been defined as a “significant radiation dose” by the Society of Interventional Radiology. Identification and analysis of interventions with high radiation doses has the potential to reduce radiation-induced injuries. Materials and methods Radiation dose data from a dose monitoring system for 19 interventional suites and 89,549 consecutive patient encounters from January 1, 2013 to August 1, 2019 at a single academic institution were reviewed. All patient encounters with Ka,r > 5000 mGy were included. All other encounters were excluded (n = 89,289). Patient demographics, medical specialty, intervention type, fluoroscopy time (minutes), dose area product (mGy·cm2), and Ka,r (mGy) were evaluated. Results There were 260 (0.3%) fluoroscopically-guided procedures with Ka,r > 5000 mGy. Of the 260 procedures which exceeded 5000 mGy, neurosurgery performed 81 (30.5%) procedures, followed by interventional radiology (n = 75; 28.2%), neurointerventional radiology (n = 55; 20.7%), and vascular surgery (n = 49; 18.4%). The procedures associated with the highest Ka,r were venous stent reconstruction performed by interventional radiology, arteriovenous malformation embolization performed by neurointerventional radiology, spinal hardware fixation by neurosurgery, and arterial interventions performed by vascular surgery. Neurointerventional radiology had the highest mean Ka,r (7,799 mGy), followed by neurosurgery (7452 mGy), vascular surgery (6849 mGy), and interventional radiology (6109 mGy). The mean Ka,r for interventional radiology performed procedures exceeding 5000 mGy was significantly lower than that for neurointerventional radiology, neurosurgery, and vascular surgery. Conclusions Fluoroscopically-guided procedures with radiation dose exceeding 5000 mGy reference point air kerma are uncommon. The results of this study demonstrate that a large proportion of cases exceeding 5000 mGy were performed by non-radiologists, who likely do not receive the same training in radiation physics, radiation biology, and dose reduction techniques as radiologists.

We developed a methodology for extending estimates of the presence-absence of trees and several tree species contained in the Canadian National Forest Inventory using nationally consistent Landsat data products. For a prototype boreal forest region of Newfoundland and Labrador, Canada, we modeled and assessed changes in the presence-absence of trees and tree species distributions over a 25-year period. Random Forest models of presence-absence of trees had an overall classification accuracy of 0.87 ± 0.019. For five tree species, overall classification accuracies were: 0.74 ± 0.017 for balsam fir; 0.75 ± 0.028 for black spruce; 0.64 ± 0.085 for trembling aspen; 0.64 ± 0.035 for tamarack; and 0.77 ± 0.041 for white birch. While the proportion of treed area increased by 8.5% over the 25-year period, the area occupied by black spruce declined by 13.5%. The area of balsam fir and white birch increased by 9.9% and 28.2%, respectively, while trembling aspen and tamarack changed by less than 5%. The map products developed and trends observed offer baseline information in support of long-term monitoring of treed area and tree species distributions. The demonstrated methods encourage development of spatially-explicit map products to complement spatially or temporally limited forest inventory datasets.

Hepatic artery aneurysms (HAA) are rare and may be seen in the setting of infection and vascular disease. Clinical presentation is variable but many are found incidentally during imaging studies. The association of HAA with focal nodular hyperplasia (FNH) is rarely reported in literature. We present the case of a 68-year-old woman found to have a hepatic artery aneurysm and hepatic mass, both within the same liver segment. FNH and hepatic adenomas share similar imaging features but have different treatments due to malignant potential of the latter, and biopsy should be performed when adenoma cannot be excluded. In this case biopsy of the mass revealed it to be FNH and the aneurysm was treated with embolization rather than surgery.