The Skill Assumption -Over-Reliance on Perception Skills in Hazard Assessment

In the analysis of human performance and human error, considerable attention is given to the cognitive processes of actors involved in error or success scenarios. Even with awareness of hindsight bias, it takes effort to understand the actions of agents in later inspection of error scenarios. One such topic of heated discussion was the perceived poor performance of pilots in the two 737 MAX MCAS-related crashes in applying the “memory item” checklist pertaining to a runaway trim. In this paper, we argue that it is not so much the reproduction of the checklist that was lacking in these scenarios, but the trigger for even starting the checklist. Not only trim run-away problems, but several other issues likewise require an instant reaction from pilots, designated as “memory items”. Rasmussen’s simplifed schematic for the “skill, rule and knowledge” taxonomy already provides the tools for properly analyzing this. The skill to provide the triggers for these reactions relies on pattern extraction from the available sensory input, and, importantly, it can only be learned in a valid training context. It is argued that re-appraisal of these items is needed, addressing explicitly the validity of the training environments that enable pilots to learn the required pattern recognition skills

Modelling Drosophila motion vision pathways for decoding the direction of translating objects against cluttered moving backgrounds

Decoding the direction of translating objects in front of cluttered moving backgrounds, accurately and efficiently, is still a challenging problem. In nature, lightweight and low-powered flying insects apply motion vision to detect a moving target in highly variable environments during flight, which are excellent paradigms to learn motion perception strategies. This paper investigates the fruit fly Drosophila motion vision pathways and presents computational modelling based on cuttingedge physiological researches. The proposed visual system model features bio-plausible ON and OFF pathways, wide-field horizontal-sensitive (HS) and vertical-sensitive (VS) systems. The main contributions of this research are on two aspects: (1) the proposed model articulates the forming of both direction-selective and direction-opponent responses, revealed as principalfeaturesofmotionperceptionneuralcircuits,inafeed-forwardmanner;(2)italsoshowsrobustdirectionselectivity to translating objects in front of cluttered moving backgrounds, via the modelling of spatiotemporal dynamics including combination of motion pre-filtering mechanisms and ensembles of local correlators inside both the ON and OFF pathways, which works effectively to suppress irrelevant background motion or distractors, and to improve the dynamic response. Accordingly, the direction of translating objects is decoded as global responses of both the HS and VS systems with positive ornegativeoutputindicatingpreferred-direction or null-direction translation.The experiments have verified the effectiveness of the proposed neural system model, and demonstrated its responsive preference to faster-moving, higher-contrast and larger-size targets embedded in cluttered moving backgrounds

Patch angioplasty during carotid endarterectomy using different materials has similar clinical outcomes

OBJECTIVE: Patch angioplasty during carotid endarterectomy is commonly used to treat carotid artery stenosis. However, the choice of which patch to use is still a matter of debate. Autologous venous material has disadvantages such as wound-related problems at the harvest site and a prolonged intervention time. These limitations can be bypassed when synthetic or biological patches are used. Both materials have been associated with divergent advantages and disadvantages. Therefore, the aim of our study was to compare the long-term follow-up outcomes in patients who received carotid endarterectomy and closure with either bovine pericardial patch or polyester patch. METHODS: A retrospective cohort study was conducted, including all patients who underwent primary carotid endarterectomy and closure with bovine pericardial patch or polyester patch between January 2010 and December 2020 at our tertiary referral center. In 2015, bovine pericardial patch was introduced as an alternative for polyester. The primary outcome was the occurrence of transient ischemic attack or cerebrovascular accident during follow-up and secondary outcomes included restenosis, reintervention, all-cause mortality, and patch infection. Cox proportional hazard models were utilized and hazard ratios with 95%-confidence interval were used to predict the above-mentioned outcomes. RESULTS: 417 carotid endarterectomy patients were included. 254 (61%) patients received bovine pericardial patch and 163 received (39%) polyester. The mean age was 70.2 ± 8.7 and 67% were male. The median follow-up time was 15 (12-27) months for bovine pericardial patch and 42 (16-60) months for polyester (p<0.001). Postoperative hematoma (≤30 days) was significantly lower in the bovine pericardial patch cohort (2% bovine pericardial patch vs 6% polyester; p=0.047). No other significant differences on short-term outcomes were found. Univariable cox regression analyses showed no significant differences between the effect estimates of polyester and bovine pericardial patch on transient ischemic attack or cerebrovascular accident (p=0.106), restenosis (p=0.211), reintervention (p=0.549), and all-cause mortality (p=0.158). No significant differences were found after adjusting for confounders in the multivariable analyses: transient ischemic attack or cerebrovascular accident, (p=0.939), restenosis (p=0.057), reintervention (p=0.193) and all-cause mortality (p=0.742). Three patients with a polyester patch had patch infection compared to none of the patients in the group who received a bovine pericardial patch. CONCLUSION: This large retrospective study showed comparable safety and durability of both bovine pericardial patch and polyester suggesting that both patch types can be safely applied for carotid endarterectomy with patch angioplasty. Patch infection was rare while absent in the bovine pericardial patch group

Clinical Response to Procedural Stroke Following Carotid Endarterectomy:A Delphi Consensus Study

Objective: No dedicated studies have been performed on the optimal management of patients with an acute stroke related to carotid intervention nor is there a solid recommendation given in the European Society for Vascular Surgery guideline. By implementation of an international expert Delphi panel, this study aimed to obtain expert consensus on the optimal management of in hospital stroke occurring during or following CEA and to provide a practical treatment decision tree. Methods: A four round Delphi consensus study was performed including 31 experts. The aim of the first round was to investigate whether the conceptual model indicating the traditional division between intra- and post-procedural stroke in six phases was appropriate, and to identify relevant clinical responses during these six phases. In rounds 2, 3, and 4, the aim was to obtain consensus on the optimal response to stroke in each predefined setting. Consensus was reached in rounds 1, 3, and 4 when ≥ 70% of experts agreed on the preferred clinical response and in round 2 based on a Likert scale when a median of 7 – 9 (most adequate response) was given, IQR ≤ 2. Results: The experts agreed (> 80%) on the use of the conceptual model. Stroke laterality and type of anaesthesia were included in the treatment algorithm. Consensus was reached in 17 of 21 scenarios (> 80%). Perform diagnostics first for a contralateral stroke in any phase, and for an ipsilateral stroke during cross clamping, or apparent stroke after leaving the operation room. For an ipsilateral stroke during the wake up phase, no formal consensus was achieved, but 65% of the experts would perform diagnostics first. A CT brain combined with a CTA or duplex ultrasound of the carotid arteries should be performed. For an ipsilateral intra-operative stroke after flow restoration, the carotid artery should be re-explored immediately (75%). Conclusion: In patients having a stroke following carotid endarterectomy, expedited diagnostics should be performed initially in most phases. In patients who experience an ipsilateral intra-operative stroke following carotid clamp release, immediate re-exploration of the index carotid artery is recommended

The Effect of Metabolic Syndrome on the Occurrence of Restenosis After Carotid Endarterectomy

Objectives: The metabolic syndrome (MetS) is a cluster of risk factors for cardiovascular disease. The effect of MetS on clinical outcome in patients with cerebrovascular disease remains largely unknown because conflicting results have been published. This study aimed to determine the influence of MetS on the occurrence of restenosis after carotid endarterectomy (CEA). Methods: All patients who underwent CEA between June 2003 and December 2014 in two tertiary academic referral centres in The Netherlands were included. MetS was defined if three or more of the following criteria were present: hypertension, obesity, high fasting serum blood glucose, high serum triglycerides, or low serum high density lipoprotein cholesterol. The primary outcome measure was the occurrence of ipsilateral restenosis after index surgery. The secondary outcome measure was (all cause) mortality during follow up. For the primary analysis, missing data were multiply imputed using multivariable imputation by chained equations. A Cox proportional hazards model was used to perform an adjusted analysis on the multiply imputed data sets. Results: A total of 1668 CEA procedures (in 1577 patients) were performed. The presence or absence of MetS could not be determined in 263 patients because of missing data. There was no significant difference in freedom from restenosis in the MetS group vs. the no-MetS group (hazard ratio [HR], 1.10; 95% confidence interval [CI] 0.98-1.23; p = .10) or in all cause mortality (HR 1.20; 95% CI 0.94-1.54; p = .14). Conclusion: This study shows that MetS does not predict restenosis after CEA. Also, the presence of MetS did not influence patient survival negatively

Control of carry-over contamination for PCR-based DNA methylation quantification using bisulfite treated DNA

In this study, we adapted the well known uracil DNA glycosylase (UNG) carry-over prevention system for PCR, and applied it to the analysis of DNA methylation based on sodium bisulfite conversion. As sodium bisulfite treatment converts unmethylated cytosine bases into uracil residues, bisulfite treated DNA is sensitive to UNG treatment. Therefore, UNG cannot be used for carry-over prevention of PCR using bisulfite treated template DNA, as not only contaminating products of previous PCR, but also the actual template will be degraded. We modified the bisulfite treatment procedure and generated DNA containing sulfonated uracil residues. Surprisingly, and in contrast to uracil, 6-sulfonyl uracil containing DNA (SafeBis DNA) is resistant to UNG. We showed that the new procedure removes up to 10 000 copies of contaminating PCR product in a closed PCR vessel without significant loss of analytical or clinical sensitivity of the DNA methylation analysis

Columnar cells necessary for motion responses of wide-field visual interneurons in Drosophila

Wide-field motion-sensitive neurons in the lobula plate (lobula plate tangential cells, LPTCs) of the fly have been studied for decades. However, it has never been conclusively shown which cells constitute their major presynaptic elements. LPTCs are supposed to be rendered directionally selective by integrating excitatory as well as inhibitory input from many local motion detectors. Based on their stratification in the different layers of the lobula plate, the columnar cells T4 and T5 are likely candidates to provide some of this input. To study their role in motion detection, we performed whole-cell recordings from LPTCs in Drosophila with T4 and T5 cells blocked using two different genetically encoded tools. In these flies, motion responses were abolished, while flicker responses largely remained. We thus demonstrate that T4 and T5 cells indeed represent those columnar cells that provide directionally selective motion information to LPTCs. Contrary to previous assumptions, flicker responses seem to be largely mediated by a third, independent pathway. This work thus represents a further step towards elucidating the complete motion detection circuitry of the fly

Effect of β2-adrenergic receptor stimulation on lung fluid in stable heart failure patients

Introduction: The purpose of this study was to determine 1) if stable heart-failure patients with reduced ejection fraction (HFrEF) have elevated extravascular lung water (EVLW) versus healthy control subjects, and 2) the effect of acute β2AR agonist inhalation on lung fluid balance. Methods: Twenty-two stable HFrEF patients and 18 age- and sex-matched healthy subjects were studied. Lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary conductance (DmCO), pulmonary capillary blood volume (Vc) (via rebreathe) and lung tissue volume (Vtis) (via computed tomography) were assessed before and within 30 min of administration of nebulized albuterol. EVLW was derived as Vtis – Vc. Results: Pre-albuterol, Vtis and EVLW were greater in HFrEF vs. control (998 ± 200 vs. 884 ± 123 ml, P = 0.041; 943 ± 202 vs. 802 ± 133 ml, P = 0.015, respectively). Albuterol decreased Vtis and EVLW in HFrEF (−4.6 ± 7.8%, P = 0.010; −4.6 ± 8.8%, P = 0.018) and control (−2.8 ± 4.9%, P = 0.029; −3.0 ± 5.7%, P = 0.045). There was an inverse relationship between pre-albuterol values and the pre- to post-albuterol change for EVLW (r2 = −0.264, P = 0.015) and DmCO (r2 = −0.343, P = 0.004) in HFrEF only. Conclusion: Lung fluid is elevated in stable HFrEF patients relative to healthy subjects. Stimulation of the β2ARs may cause fluid removal in HFrEF, especially in patients who exhibit greater evidence for increased lung water at baseline

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available