Crustal Structure and Mesozoic Tectonic Evolution of Conjugate Volcanic Passive Margins of the South-Central and South Atlantic Oceans

Volcanic passive margins (VPM) initiate with the eruption of flood basalts in continental rift settings that overlie an active mantle plume. Magmatism on conjugate VPM’s increases in volume and intensity during continued lithospheric stretching and includes the generation of igneous belts ranging from 10-200+ km in width and to 8-24 km-thick. Conjugate volcanic passive margin belts include seaward-dipping reflectors (SDR’s) whose dips range from 0 to 20°. I use 33,000 line km of 40-km-record 2D seismic reflection data to identify a VPM beneath the Demerara Rise, offshore Suriname and to investigate VPM’s along the conjugate margins of the South America (Brazil and Uruguay) and West Africa (Namibia). My 5500 km of 2D seismic data from the Demerara Rise - previously characterized as a continental plateau – reveals a basement composed of >22- km-thick, 250-km-long, steeply-dipping (>20°) packages of SDR’s related to Jurassic rifting of North America and South America. 2D gravity modeling and VPM analogs are used to support its proposed magmatic origin. I investigated the crustal structure of conjugate VPMs in Uruguay/Southern Brazil and Namibia using 27,500 km of 2D seismic data. An asymmetrical distribution of SDRs is proposed as a consequence of increased plate velocities relative to a fixed mantle position. The faster plate – South America - contains 30% less volume of SDR’s (201,700 km3) compared to the slower plate – Africa (296,400 km3). I identify rifting along crustal weaknesses inherited from Paleozoic orogenic belts trending either parallel or perpendicular to the Cretaceous rift margin. I calculate crustal stretching factors (Δc) for: 1) rift-orthogonal orogenic belts (Δc=4.3-5); 2) suture zones and rift-parallel orogenic belts (Δc=2.5-3.5). Obliquely-oriented belts show evidence of moderate thinning with intermediate thinning factors. The relationship between crustal and trend of crustal fabric is supported by my compilation of thinning factors from other rift zones worldwideEarth and Atmospheric Sciences, Department o

Response to Open Peer Commentaries on "Diagnosis By Television Documentary: Professional Responsibilities in Informal Encounters".

In presenting the situation of a health professional witnessing an instance of misdiagnosis and mistreatment in a television documentary, we hoped to stimulate discussion of the professional responsibilities of health workers in informal encounters in a rapidly changing environment comprising print, television, and more recently social media platforms. The commentaries on our article do not disappoint in this respect, providing insightful and sometimes challenging reactions to the position we outlined in response to our original case. In our reply here, we choose to focus on two themes running through all of the commentaries: (1) the distinction between axiological and deontic perspectives invoked by Salloch, and the open-endedness of the former that we see as crucial in addressing the constantly changing media landscape through which health workers may confront medical need; and (2) the role of institutional, structural, and social factors in constraining or enabling virtuous professional practice—suggesting perhaps a further need for health workers to take action directly against structural injustices that prevent them from fulfilling their professional responsibilities

Do patients want choice? An observational study of neurology consultations

Objectives: To determine how often patients are given choice in neurology outpatient consultations and whether choice is associated with greater patient satisfaction. Methods: Prospective study in outpatient clinics in two United Kingdom centres. Interactions between 14 neurologists and 223 patients were studied. Participating doctors and patients completed post-appointment questionnaires asking whether choice had been offered/perceived. Patients completed the Medical Interview Satisfaction Scale 21 (MISS-21). Results: Choice was reported after most encounters (patients 71.8%, neurologists 67.9%). Patients and Neurologists failed to agree about whether choice was offered after 32% of consultations. Choice was not associated with increased patient satisfaction. In fact, satisfaction was greater when no choice had been offered (p = 0.05). Satisfaction scores were also greater when doctors were more certain about the diagnosis and when symptoms were considered explained by a medical condition (p ≤ 0.001). Conclusions: Choice featured in the majority of clinical interactions but clinicians and patients often disagreed whether this was the case. Choice was not associated with greater patient satisfaction. Practice implications: Clinicians need to be very explicit if they want patients to know that they are being given choices. Choice is not necessarily valued by patients in all clinical interactions

The importance of semiological information based on epileptic seizure history

Semiology is the backbone of any correct categorization of seizures, as epileptic or not, focal or bilateral, and is fundamental to elucidating how they are anatomically generated in the brain. An anatomical hypothesis derived from seizure history is the precondition for optimally designed ancillary studies. Without understanding seizure semiology, no rational therapy is possible. This article describes the semiological approach using patient history based on full use of patients’ self-reports as well as descriptions by witnesses. Auras represent the subjective aspects of seizures and provide important semiological clues as observable signs, sometimes including rather precise direct anatomical information. Methods of extracting, facilitating and analysing self-reports including linguistic conversation analysis are presented in detail. It is highlighted that prodromes, seizure triggers and reflex epileptic mechanisms can provide crucial information for diagnostics and therapy. Special issues considering seizure semiology in children are discussed in a separate section. Other sections are dedicated to the two most important issues of differential diagnosis: how to distinguish (1) focal from “generalized” epilepsies, particularly when focal seizure phenomena appear in a bilateral epilepsy; and (2) epileptic from a series of non-epileptic events

Generating the perception of choice: the remarkable malleability of option-listing

The normative view that patients should be offered more choice both within and beyond the UK's National Health Service (NHS) has been increasingly endorsed. However, there is very little research on whether - and how - this is enacted in practice. Based on 223 recordings of neurology outpatient consultations and participants' subsequent self-reports, this article shows that 'option-listing' is a key practice for generating the perception of choice. The evidence is two-fold: first, we show that neurologists and patients overwhelmingly reported that choice was offered in those consultations where option-listing was used; second, we demonstrate how option-listing can be seen, in the interaction itself, to create a moment of choice for the patient. Surprisingly, however, we found that even when the patient resisted making the choice or the neurologist adapted the practice of option-listing in ways that sought acceptance of the neurologist's own recommendation, participants still agreed that a choice had been offered. There was only one exception: despite the use of option-listing, the patient reported having no choice, whereas the neurologist reported having offered a choice. We explore this deviant case in order to shed light on the limits of option-listing as a mechanism for generating the perception of choice

Early Seizure Detection Based on Cardiac Autonomic Regulation Dynamics

Epilepsy is a neurological disorder that causes changes in the autonomic nervous system. Heart rate variability (HRV) reflects the regulation of cardiac activity and autonomic nervous system tone. The early detection of epileptic seizures could foster the use of new treatment approaches. This study presents a new methodology for the prediction of epileptic seizures using HRV signals. Eigendecomposition of HRV parameter covariance matrices was used to create an input for a support vector machine (SVM)-based classifier. We analyzed clinical data from 12 patients (9 female; 3 male; age 34.5 ± 7.5 years), involving 34 seizures and a total of 55.2 h of interictal electrocardiogram (ECG) recordings. Data from 123.6 h of ECG recordings from healthy subjects were used to test false positive rate per hour (FP/h) in a completely independent data set. Our methodological approach allowed the detection of impending seizures from 5 min to just before the onset of a clinical/electrical seizure with a sensitivity of 94.1%. The FP rate was 0.49 h−1 in the recordings from patients with epilepsy and 0.19 h−1 in the recordings from healthy subjects. Our results suggest that it is feasible to use the dynamics of HRV parameters for the early detection and, potentially, the prediction of epileptic seizures

Strange Particles in Dense Matter and Kaon Condensates

We discuss the role of strangeness in dense matter and especially in neutron stars. The early (in density) introduction of hyperons found in many calculations is probably delayed by the decrease in vector mean field acting on the neutron. The decrease results from both conventional many-body rescattering effects and from the movement towards asymptotic freedom at high densities. Subthreshold $K^-$-meson production by the KaoS collaboration at GSI shows that the $K^-$-mass must be substantially lowered, by $\gtrsim$ 200 MeV at $\rho\sim 2\rho_0$. It is shown that explicit chiral symmetry breaking through the kaon mass may be responsible for $\Sigma^-$-nucleon and $\Xi^-$-nucleon scalar attraction being weaker than obtained by simple quark scaling. The normal mode of the strangeness minus, charge $e^-$, excitation is constructed as a linear combination of $K^-$-meson and $\Sigma^-$, neutron-hole state. Except for zero momentum, where the terms are unmixed the "kaesobar" is a linear combination of these two components.Comment: 10 pages, 8 postscript figures, Talk given at the International Conference on Hypernuclear and Strange Particle Physics (HYP97), Brookhaven Nat'l Lab., USA, October 13-18, 1997, to be published in Nucl. Phys.

Data augmentation using generative networks to identify dementia

Data limitation is one of the most common issues in training machine learning classifiers for medical applications. Due to ethical concerns and data privacy, the number of people that can be recruited to such experiments is generally smaller than the number of participants contributing to non-healthcare datasets. Recent research showed that generative models can be used as an effective approach for data augmentation, which can ultimately help to train more robust classifiers sparse data domains. A number of studies proved that this data augmentation technique works for image and audio data sets. In this paper, we investigate the application of a similar approach to different types of speech and audio-based features extracted from interactions recorded with our automatic dementia detection system. Using two generative models we show how the generated synthesized samples can improve the performance of a DNN based classifier. The variational autoencoder increased the F-score of a four-way classifier distinguishing the typical patient groups seen in memory clinics from 58% to around 74%, a 16% improvement

Pion-Lambda-Sigma Coupling Extracted from Hyperonic Atoms

The latest measurements of the atomic level width in Sigma-hyperonic Pb atom offer the most accurate datum in the region of low-energy Sigma-hyperon physics. Atomic widths are due to the conversion of Sigma-nucleon into Lambda-nucleon. In high angular momentum states this conversion is dominated by the one-pion exchange. A joint analysis of the data of the scattering of negative-Sigma on proton converting into a Lambda and a neutron and of the atomic widths allows to extract a pseudovector pion-hyperon-Sigma coupling constant of 0.048 with a statistical error of +-0.005 and a systematic one of +-0.004. This corresponds to a pseudoscalar coupling constant of 13.3 with a statistical uncertainty of 1.4 and a systematic one of 1.1.Comment: 12 pages, 1 figure, Use of Revtex.st