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The linear stability of plane Couette flow is investigated when the plates are horizontal, and the fluid is stably stratified with a cubic basic density profile. The disturbances are treated as inviscid and diffusion of the density field is neglected. Previous studies have shown that this density profile can develop multiple neutral curves, despite the stable stratification, and the fact that plane Couette flow of homogeneous fluid is stable. It is shown that when the neutral curves are plotted with wave angle on one axis, and location of the density inflexion point on the other axis, they produce a self-similar fractal pattern. The repetition on smaller and smaller scales occurs in the limit when the waves are highly oblique, i.e. longitudinal vortices almost aligned with the flow; the corresponding limit for two-dimensional waves is that of strong buoyancy/weak flow. The fractal set of neutral curves also represents a fractal of bifurcation points at which nonlinear solutions can be continued from the trivial state, and these may be helpful for understanding turbulent states. This may be the first example of a fractal generated by a linear ordinary differential equation.
The Reinforcement Sensitivity Theory of Personality has as its main foundation a Behavioural Inhibition System (BIS), defined by anxiolytic drugs, in which high trait sensitivity should lead to internalising, anxiety, disorders. Conversely, it has been suggested that low BIS sensitivity would be a characteristic of externalising disorders. BIS output should lead to increased arousal and attention as well as behavioural inhibition. Here, therefore, we tested whether an externalising disorder, Attention Deficit Hyperactivity Disorder (ADHD), involves low BIS sensitivity. Goal-Conflict-Specific Rhythmicity (GCSR) in an auditory Stop Signal Task is a right frontal EEG biomarker of BIS function. We assessed children diagnosed with ADHD-I (inattentive) or ADHD-C (combined) and healthy control groups for GCSR in: a) an initial smaller study in Dunedin, New Zealand (population ~120,000: 15 control, 10 ADHD-I, 10 ADHD-C); and b) a main larger one in Tehran, Iran (population ~9 [city]-16 [metropolis] million: 27 control, 18 ADHD-I, 21 ADHD-C). GCSR was clear in controls (particularly at 6–7 Hz) and in ADHD-C (particularly at 8–9 Hz) but was reduced in ADHD-I. Reduced attention and arousal in ADHD-I could be due, in part, to BIS dysfunction. However, hyperactivity and impulsivity in ADHD-C are unlikely to reflect reduced BIS activity. Increased GCSR frequency in ADHD-C may be due to increased input to the BIS. BIS dysfunction may contribute to some aspects of ADHD (and potentially other externalising disorders) and to some differences between the ADHD subtypes but other prefrontal systems (and, e.g. dopamine) are also important.
Appendicitis is a common surgical condition that frequently requires diagnostic imaging. Abdominal computed tomography (CT) is the gold standard for diagnosing appendicitis. Ultrasound offers a radiation-free modality; however, its availability outside business hours is limited in many emergency departments (EDs). The purpose of this study is to evaluate the test characteristics of emergency physician-performed point-of-care ultrasound (POCUS) to diagnose appendicitis in a Canadian ED.
A health records review was performed on all ED patients who underwent POCUS to diagnose appendicitis from December 1, 2010 to December 4, 2015. The sensitivity, specificity, and likelihood ratios were calculated. The gold standard used for diagnosis was pathology, laparoscopy, CT scans, and a radiologist-performed ultrasound.
Ninety patients were included in the study, and 24 were diagnosed with appendicitis on POCUS. Ultimately, 18 were confirmed to have appendicitis through radiologist-performed imaging, laparoscopy, and pathology. The sensitivity and specificity of POCUS to diagnose appendicitis were 69.2% (95% CI, 48.1%-84.9%) and 90.6% (95% CI, 80.0%-96.1%), respectively.
POCUS has a high specificity for diagnosing acute appendicitis and has very similar characteristics to those of a radiologist-performed ultrasound. These findings are consistent with the current literature and have the potential to decrease patient morbidity, diagnostic delays, ED length of stay, and need for additional imaging.
Dysbiotic gut microbiota have been implicated in human disease. Diet-based therapeutic strategies have been used to manipulate the gut microbiota towards a more favourable profile. However, it has been demonstrated that large inter-individual variability exists in gut microbiota response to a dietary intervention. The primary objective of this study was to investigate whether habitually low dietary fibre (LDF) v. high dietary fibre (HDF) intakes influence gut microbiota response to an inulin-type fructan prebiotic. In this randomised, double-blind, placebo-controlled, cross-over study, thirty-four healthy participants were classified as LDF or HDF consumers. Gut microbiota composition (16S rRNA bacterial gene sequencing) and SCFA concentrations were assessed following 3 weeks of daily prebiotic supplementation (Orafti® Synergy 1; 16 g/d) or placebo (Glucidex® 29 Premium; 16 g/d), as well as after 3 weeks of the alternative intervention, following a 3-week washout period. In the LDF group, the prebiotic intervention led to an increase in Bifidobacterium (P=0·001). In the HDF group, the prebiotic intervention led to an increase in Bifidobacterium (P<0·001) and Faecalibacterium (P=0·010) and decreases in Coprococcus (P=0·010), Dorea (P=0·043) and Ruminococcus (Lachnospiraceae family) (P=0·032). This study demonstrates that those with HDF intakes have a greater gut microbiota response and are therefore more likely to benefit from an inulin-type fructan prebiotic than those with LDF intakes. Future studies aiming to modulate the gut microbiota and improve host health, using an inulin-type fructan prebiotic, should take habitual dietary fibre intake into account.
Historians and social scientists have relied on contemporaneous textual accounts to document African American mobility in the immediate aftermath of emancipation after the Civil War, but they have interpreted them in widely varying ways. Some emphasize large-scale migration across the South, while others suggest that most movements were local and limited. This research tracks the early or “first wave” of African American migrants between 1865 and 1867 within and out of the South in an attempt to map the motion taking place after the war and to document the scale, direction, and intensity of African American mobility in the period between 1865 and 1867. The Freedmen's Bureau records indicate certain kinds of movements within the South, while our census methodology shows that there was more movement out of the South than accounted for in the Freedmen's Bureau labor records or previously accounted for in the historiography. Further, we observe two types of movement: short-term migration based on one-year contracts, perhaps returning to the point of origin, and another movement not always mediated through the Freedmen's Bureau that was more long term, but also subject to the freedperson's return to the point of origin. We seek to chart the process of emancipation over time and across space, detecting spatial patterns on an otherwise highly variable individual experience. No study has used the Freedmen's Bureau labor contracts to trace African American labor movements, and no study has deployed the 1880 individual census data to examine African American migration based on birthplace cohorts.
Introduction: Atrial fibrillation (AF) is the most common sustained arrhythmia affecting 1-2% of the population. Oral anticoagulation (OAC) reduces stroke risk by 60-80% in AF patients, but only 50% of indicated patients receive OAC. Many patients present to the ED with AF due to arrhythmia symptoms, however; lack of OAC prescription in the ED has been identified as a significant gap in the care of AF patients. Methods: This was a multi-center, pragmatic, three-phase before-after study, in three Canadian sites. Patients who presented to the ED with electrocardiographically (ECG) documented, nonvalvular AF and were discharged home were included. Phase 1 was a retrospective chart review to determine OAC prescription of AF patients in each ED; Phase 2 was a low-intensity knowledge translation intervention where a simple OAC-prescription tool for ED physicians with subsequent short-term OAC prescription was used, as well as an AF patient education package and a letter to family physicians; phase 3 incorporated Phase 2 interventions, but added immediate follow-up in a community AF clinic. The primary outcome of the study was the rate of new OAC prescriptions at ED discharge in AF patients who were OAC eligible and were not on OAC at presentation. Results: A total of 632 patients were included from June, 2015-November, 2016. ED census ranged from 30000-68000 annual visits. Mean age was 71±15, 67±12, 67±13 years, respectively. 47.5% were women, most responsible ED diagnosis was AF in 75.8%. The mean CHA2DS2-VASc score was 2.6±1.8, with no difference amongst groups. There were 266 patients eligible for OAC and were not on this at presentation. In this group, the prescription of new OAC was 15.8% in Phase 1 as compared to 54% and 47%, in Phases 2 and 3, respectively. After adjustment for center, components of the CHA2DS2-VASc score, prior risk of bleeding and most responsible ED diagnosis, the odds ratio for new OAC prescription was 8.0 (95%CI (3.5,18.3) p<0.001) for Phase 3 vs 1, and 10.0 (95%CI (4.4,22.9) p<0.001), for Phase 2 vs 1). No difference in OAC prescription was seen between Phases 2 and 3. Conclusion: Use of a simple OAC-prescription tool was associated with an increase in new OAC prescription in the ED for eligible patients with AF. Further testing in a rigorous study design to assess the effect of this practice on stroke prevention in the AF patients who present to the ED is indicated.
This article examines the likely role of competition in the regulatory analysis of bank mergers in China. Despite financial reforms, the banking sector remains subject to a complex web of financial regulation, with industrial policy favouring stability to facilitate national economic development. While there are currently no Ministry of Commerce (MOFCOM) bank merger determinations under the Anti-Monopoly Law (AML), examples of MOFCOM’s merger analysis in other sensitive industries diverge from a pure competition-based analysis, favouring grounds linked to national economic development broadly within the terms of the AML. Given the importance of banking to the Chinese economy, this article argues that competition is unlikely to play a large part in any assessment of bank mergers by MOFCOM, particularly where a foreign bank is involved. Instead, issues linked to ‘national economic development’ and stability are likely to play the most important role, leading to less predictable merger approval outcomes.
Substantial policy, communication and operational gaps exist between mental health services and the police for individuals with enduring mental health needs.
To map and cost pathways through mental health and police services, and to model the cost impact of implementing key policy recommendations.
Within a case-linkage study, we estimated 1-year individual-level healthcare and policing costs. Using decision modelling, we then estimated the potential impact on costs of three recommended service enhancements: street triage, Mental Health Act assessments for all Section 136 detainees and outreach custody link workers.
Under current care, average 1-year mental health and police costs were £10 812 and £4552 per individual respectively (n = 55). The cost per police incident was £522. Models suggested that each service enhancement would alter per incident costs by between −8% and +6%.
Recommended enhancements to care pathways only marginally increase individual-level costs.
A better therapeutic relationship predicts better outcomes. However,
there is no trial-based evidence on how to improve therapeutic
relationships in psychosis.
To test the effectiveness of communication training for psychiatrists on
improving shared understanding and the therapeutic relationship (trial
In a cluster randomised controlled trial in the UK, 21 psychiatrists were
randomised. Ninety-seven (51% of those approached) out-patients with
schizophrenia/schizoaffective disorder were recruited, and 64 (66% of the
sample recruited at baseline) were followed up after 5 months. The
intervention group received four group and one individualised session.
The primary outcome, rated blind, was psychiatrist effort in establishing
shared understanding (self-repair). Secondary outcome was the therapeutic
Psychiatrists receiving the intervention used 44% more self-repair than
the control group (adjusted difference in means 6.4, 95% CI 1.46–11.33,
P<0.011, a large effect) adjusting for baseline
self-repair. Psychiatrists rated the therapeutic relationship more
positively (adjusted difference in means 0.20, 95% CI 0.03–0.37,
P = 0.022, a medium effect), as did patients
(adjusted difference in means 0.21, 95% CI 0.01–0.41, P
= 0.043, a medium effect).
Shared understanding can be successfully targeted in training and
improves relationships in treating psychosis.
In papers published in the 25 years following his famous 1964 proof, John Bell refined and reformulated his views on locality and causality. Although his formulations of local causality were in terms of probability, he had little to say about that notion. But assumptions about probability are implicit in his arguments and conclusions. Probability does not conform to these assumptions when quantum mechanics is applied to account for the particular correlations Bell argues are locally inexplicable. This account involves no superluminal action and there is even a sense in which it is local, but it is in tension with the requirement that the direct causes and effects of events be nearby.
I never met John Bell, but his writings have supplied me with a continual source of new insights as I read and reread them over 40 years. As I worked toward a rather different understanding of quantum mechanics he was foremost in my mind as a severe but honest critic of such attempts. We all would love to know what Einstein would have made of Bell's theorem. I confess that the deep regret I feel that Bell cannot respond to this paper is sometimes assuaged by a sense of relief.
Locality and Local Causality
In his seminal 1964 paper , John Bell expressed locality as the requirement
that the result of a measurement on one system be unaffected by operations on a distant system with which it has interacted in the past.
[2, p. 14]
This seems to require that the result of a measurement would have been the same, no matter what operations had been performed on such a distant system. But suppose the result of a measurement were the outcome of an indeterministic process. Then the result of the measurement might have been different even if exactly the same operations (if any) had been performed on that distant system. So can no indeterministic theory satisfy the locality requirement? Bell felt no need to address that awkward question in his 1964 paper , since he took the EPR argument to establish that any additional variables needed to restore locality and causalitywould have to determine a unique result of ameasurement.
Introduction: Appendicitis is a common surgical condition that frequently requires patients to undergo diagnostic imaging. Abdominal computed tomography is the gold standard imaging technique for the diagnosis of appendicitis, but exposes patients to radiation. Ultrasound offers an alternate radiation-free imaging modality for appendicitis. However, the availability of ultrasound during off-hours is limited in many Emergency departments (EDs). Clinician performed point-of-care ultrasound (POCUS) is increasingly used by emergency physicians as a bedside tool to evaluate suspected appendicitis. The purpose of this study is to evaluate the test characteristics of emergency physician performed POCUS to diagnose appendicitis in a Canadian ED. Methods: A pragmatic, retrospective chart review was performed on all patients for whom a POCUS was performed to diagnose appendicitis at St. Joseph’s Healthcare Hamilton in Ontario from December 1, 2010 to December 4, 2015. All POCUS scans were performed by physicians with Registered Diagnostic Medical Sonographer (RDMS) credentials or resident physicians undergoing POCUS fellowship training. All scans were over-read by RDMS credentialed faculty and subject to a rigorous quality assurance (QA) process. POCUS findings and patient outcomes were reported. Results: A total of 90 patients were included in the study. 24 patients were diagnosed with appendicitis on POCUS. Ultimately, 18 were diagnosed with appendicitis through formal imaging, laparoscopy, and pathology. The sensitivity and specificity for POCUS to diagnose appendicitis was found to be 69.2% (95% CI, 48.1%-84.9%) and 90.6% (95% CI, 80.0%-96.1%) respectively. Conclusion: Bedside ultrasound is a reliable imaging modality for ruling in acute appendicitis. In cases where POCUS is negative or indeterminate for appendicitis, further imaging should be obtained as clinical suspicion warrants. The use of POCUS has the potential to reduce patient exposure to ionizing radiation and decrease the costs of obtaining CT scans, while hastening the process of achieving definitive management through earlier surgical consultation.
Introduction: The recently published ProMISe, ARISE and ProCESS trials demonstrated that protocol-based resuscitation (EGDT) of ER patients in whom septic shock was diagnosed did not improve outcome when compared to usual care. The objective of this project was to survey McMaster emergency physicians in areas including sepsis definition, clinical recognition in adults, self-rated skills assessment, attitudes towards skills augmentation and compare results to the cohort surveyed 11 years ago, close to the introduction of EGDT. Methods: Full time faculty at McMaster’s Department of Emergency Medicine and ER residents were surveyed anonymously using an electronic survey. The questions covered demographics and training data, identification of septic patients, sepsis intervention and attitudes towards skills augmentation. Results: A total of 18 physicians responded to the electronic survey to date. All respondents were able to correctly input definitions for SIRS, sepsis, severe sepsis and septic shock. The majority of respondents felt the best strategy to identify potentially septic adults involved monitoring abnormal vital signs (67%) with some stating serum lactate assessment (33%). Of the 11 possible interventions options provided to care for septic patients, respondents appeared more comfortable with placement of lines, giving vasopressors and appropriate use of fluids for resuscitation. This was compared to more specialized interventions like initiating IV steroids in vasopressor dependant shock despite adequate fluid loading. 22% of respondents believed that patients without respiratory compromise with clinically severe sepsis should be intubated which was found to be 48% in the previous cohort surveyed 11 years ago. 78% believed patients in septic shock without respiratory comprise should be intubated, reassuringly similar to the previous survey result of 87%. Conclusion: Emergency physicians at our Canadian institution are comfortable with the skill set required to care for patients with sepsis. Respondents surveyed to date were all comfortable with important resuscitative measures including accurate identification, placement of lines and appropriate fluid administration and were receptive to additional training. Our study emphasizes that our physicians have the skill set to identify and provide care for sepsis using their clinical judgment in cases that may not require protocolized based care.
Empirical evidence from dialogue, both corpus and experimental, highlights the importance of interaction in language use – and this raises some questions for Christiansen & Chater's (C&C's) proposals. We endorse C&C's call for an integrated framework but argue that their emphasis on local, individual production and comprehension makes it difficult to accommodate the ubiquitous, interactive, and defeasible processes of clarification and repair in conversation.
It may be true that “groups need selves,” as Baumeister et al. contend. However, certain types of selfhood and too much selfhood can both be detrimental to group functioning. I draw on theory and research on dual selves in work groups and teams to outline boundary conditions to the hypothesis that emphasizing individual selves yields positive effects for groups.