Defectors cannot be detected during"small talk" with strangers.

To account for the widespread human tendency to cooperate in one-shot social dilemmas, some theorists have proposed that cooperators can be reliably detected based on ethological displays that are difficult to fake. Experimental findings have supported the view that cooperators can be distinguished from defectors based on "thin slices" of behavior, but the relevant cues have remained elusive, and the role of the judge's perspective remains unclear. In this study, we followed triadic conversations among unacquainted same-sex college students with unannounced dyadic one-shot prisoner's dilemmas, and asked participants to guess the PD decisions made toward them and among the other two participants. Two other sets of participants guessed the PD decisions after viewing videotape of the conversations, either with foreknowledge (informed), or without foreknowledge (naïve), of the post-conversation PD. Only naïve video viewers approached better-than-chance prediction accuracy, and they were significantly accurate at predicting the PD decisions of only opposite-sexed conversation participants. Four ethological displays recently proposed to cue defection in one-shot social dilemmas (arms crossed, lean back, hand touch, and face touch) failed to predict either actual defection or guesses of defection by any category of observer. Our results cast doubt on the role of "greenbeard" signals in the evolution of human prosociality, although they suggest that eavesdropping may be more informative about others' cooperative propensities than direct interaction

On Two Complementary Types of Total Time Derivative in Classical Field Theories and Maxwell's Equations

Close insight into mathematical and conceptual structure of classical field theories shows serious inconsistencies in their common basis. In other words, we claim in this work to have come across two severe mathematical blunders in the very foundations of theoretical hydrodynamics. One of the defects concerns the traditional treatment of time derivatives in Eulerian hydrodynamic description. The other one resides in the conventional demonstration of the so-called Convection Theorem. Both approaches are thought to be necessary for cross-verification of the standard differential form of continuity equation. Any revision of these fundamental results might have important implications for all classical field theories. Rigorous reconsideration of time derivatives in Eulerian description shows that it evokes Minkowski metric for any flow field domain without any previous postulation. Mathematical approach is developed within the framework of congruences for general 4-dimensional differentiable manifold and the final result is formulated in form of a theorem. A modified version of the Convection Theorem provides a necessary cross-verification for a reconsidered differential form of continuity equation. Although the approach is developed for one-component (scalar) flow field, it can be easily generalized to any tensor field. Some possible implications for classical electrodynamics are also explored.Comment: no figure

Coming in Warm: Qualitative Study and Concept Map to Cultivate Patient‐Centered Empathy in Emergency Care

Background Increased empathy may improve patient perceptions and outcomes. No training tool has been derived to teach empathy to emergency care providers. Accordingly, we engaged patients to assist in creating a concept map to teach empathy to emergency care providers. Methods We recruited patients, patient caretakers and patient advocates with emergency department experience to participate in three separate focus groups (n = 18 participants). Facilitators guided discussion about behaviors that physicians should demonstrate in order to rapidly create trust, enhance patient perception that the physician understood the patient's point of view, needs, concerns, fears, and optimize patient/caregiver understanding of their experience. Verbatim transcripts from the three focus groups were read by the authors and by consensus, 5 major themes with 10 minor themes were identified. After creating a codebook with thematic definitions, one author reviewed all transcripts to a library of verbatim excerpts coded by theme. To test for inter‐rater reliability, two other authors similarly coded a random sample of 40% of the transcripts. Authors independently chose excerpts that represented consensus and strong emotional responses from participants. Results Approximately 90% of opinions and preferences fell within 15 themes, with five central themes: Provider transparency, Acknowledgement of patient's emotions, Provider disposition, Trust in physician, and Listening. Participants also highlighted the need for authenticity, context and individuality to enhance empathic communication. For empathy map content, patients offered example behaviors that promote perceptions of physician warmth, respect, physical touch, knowledge of medical history, explanation of tests, transparency, and treating patients as partners. The resulting concept map was named the “Empathy Circle”. Conclusions Focus group participants emphasized themes and tangible behaviors to improve empathy in emergency care. These were incorporated into the “Empathy Circle”, a novel concept map that can serve as the framework to teach empathy to emergency care providers

The geometry of manifolds and the perception of space

This essay discusses the development of key geometric ideas in the 19th century which led to the formulation of the concept of an abstract manifold (which was not necessarily tied to an ambient Euclidean space) by Hermann Weyl in 1913. This notion of manifold and the geometric ideas which could be formulated and utilized in such a setting (measuring a distance between points, curvature and other geometric concepts) was an essential ingredient in Einstein's gravitational theory of space-time from 1916 and has played important roles in numerous other theories of nature ever since.Comment: arXiv admin note: substantial text overlap with arXiv:1301.064

Emergency Physicians Are Able to Detect Right Ventricular Dilation With Good Agreement Compared to Cardiology

Objective Focused cardiac ultrasound (FOCUS) is a useful tool in evaluating patients presenting to the emergency department (ED) with acute dyspnea. Prior work has shown that right ventricular (RV) dilation is associated with repeat hospitalizations and shorter life expectancy. Traditionally, RV assessment has been evaluated by cardiologist-interpreted comprehensive echocardiography. The primary goal of this study was to determine the inter-rater reliability between emergency physicians (EPs) and a cardiologist for determining RV dilation on FOCUS performed on ED patients with acute dyspnea. Methods This was a prospective, observational study at two urban academic EDs; patients were enrolled if they had acute dyspnea and a computed tomographic pulmonary angiogram without acute disease. All patients had an EP-performed FOCUS to assess for RV dilation. RV dilation was defined as an RV to left ventricular ratio greater than 1. FOCUS interpretations were compared to a blinded cardiologist FOCUS interpretation using agreement and kappa statistics. Results Of 84 FOCUS examinations performed on 83 patients, 17% had RV dilation. Agreement and kappa, for EP-performed FOCUS for RV dilation were 89% (95% confidence interval [CI] 80–95%) and 0.68 (95% CI 0.48–0.88), respectively. Conclusions Emergency physician sonographers are able to detect RV dilation with good agreement when compared to cardiology. These results support the wider use of EP-performed FOCUS to evaluate for RV dilation in ED patients with dyspnea

Effect of well-width on the electro-optical properties of a quantum well

We record photoreflectance from Ge/GeSi modulation doped quantum wells possessing $10^4$ V/cm perpendicular electric fields. Qualitatively very different spectra are obtained from samples of well-width 100 \AA and 250 \AA. Comparing the wavefunctions calculated from an $8 \times 8$ \textbf{k.p} theory, we find that while they remain confined in the narrower 100 \AA QW, the electric field causes them to tunnel into the forbidden gap in the 250 \AA\ well. This implies that the samples should show a transition from the quantum confined Franz-Keldysh effect to the bulk-like Franz-Keldysh effect. Close to the band-edge where Franz-Keldysh effects are important, simulated photoreflectance spectra reproduce the essential features of the experiment, without any adjustable parameters.Comment: 8 pages, 8 figures. Submitted to Phys. Rev.

Outpatient treatment of low-risk venous thromboembolism with monotherapy oral anticoagulation: patient quality of life outcomes and clinician acceptance

BACKGROUND: Oral monotherapy anticoagulation has facilitated home treatment of venous thromboembolism (VTE) in outpatients. OBJECTIVES: The aim of this study was to measure efficacy, safety, as well as patient and physician perceptions produced by a protocol that selected VTE patients as low-risk patients by the Hestia criteria, and initiated home anticoagulation with an oral factor Xa antagonist. METHODS: Patients were administered the Venous Insufficiency Epidemiological and Economic Study Quality of life/Symptoms questionnaire [VEINEs QoL/Sym] and the physical component summary [PCS] from the Rand 36-Item Short Form Health Survey [SF36]). The primary outcomes were VTE recurrence and hemorrhage at 30 days. Secondary outcomes compared psychometric test scores between patients with deep vein thrombosis (DVT) to those with pulmonary embolism (PE). Patient perceptions were abstracted from written comments and physician perceptions specific to PE outpatient treatment obtained from structured survey. RESULTS: From April 2013 to September 2015, 253 patients were treated, including 67 with PE. Within 30 days, 2/253 patients had recurrent DVT and 2/253 had major hemorrhage; all four had DVT at enrollment. The initial PCS scores did not differ between DVT and PE patients (37.2±13.9 and 38.0±12.1, respectively) and both DVT and PE patients had similar improvement over the treatment period (42.2±12.9 and 43.4±12.7, respectively), consistent with prior literature. The most common adverse event was menorrhagia, present in 15% of women. Themes from patient-written responses reflected satisfaction with increased autonomy. Physicians' (N=116) before-to-after protocol comfort level with home treatment of PE increased 48% on visual analog scale. CONCLUSION: Hestia-negative VTE patients treated with oral monotherapy at home had low rates of VTE recurrence and bleeding, as well as quality of life measurements similar to prior reports

Derivation of a screening tool to identify patients with right ventricular dysfunction or tricuspid regurgitation after negative computerized tomographic pulmonary angiography of the chest

Many dyspneic patients who undergo computerized tomographic pulmonary angiography (CTPA) for presumed acute pulmonary embolism (PE) have no identified cause for their dyspnea yet have persistent symptoms, leading to more CTPA scanning. Right ventricular (RV) dysfunction or overload can signal treatable causes of dyspnea. We report the rate of isolated RV dysfunction or overload after negative CTPA and derive a clinical decision rule (CDR). We performed secondary analysis of a multicenter study of diagnostic accuracy for PE. Inclusion required persistent dyspnea and no PE. Echocardiography was ordered at clinician discretion. A characterization of isolated RV dysfunction or overload required normal left ventricular function and RV hypokinesis, or estimated RV systolic pressure of at least 40 mmHg. The CDR was derived from bivariate analysis of 97 candidate variables, followed by multivariate logistic regression. Of 647 patients, 431 had no PE and persistent dyspnea, and 184 (43%) of these 431 had echocardiography ordered. Of these, 64 patients (35% [95% confidence interval (CI): 28%-42%]) had isolated RV dysfunction or overload, and these patients were significantly more likely to have a repeat CTPA within 90 days (P = .02, [Formula: see text] test). From univariate analysis, 4 variables predicted isolated RV dysfunction: complete right bundle branch block, normal CTPA scan, active malignancy, and CTPA with infiltrate, the last negatively. Logistic regression found only normal CTPA scanning significant. The final rule (persistent dyspnea + normal CTPA scan) had a positive predictive value of 53% (95% CI: 37%-69%). We conclude that a simple CDR consisting of persistent dyspnea plus a normal CTPA scan predicts a high probability of isolated RV dysfunction or overload on echocardiography

Multivariate Granger Causality and Generalized Variance

Granger causality analysis is a popular method for inference on directed interactions in complex systems of many variables. A shortcoming of the standard framework for Granger causality is that it only allows for examination of interactions between single (univariate) variables within a system, perhaps conditioned on other variables. However, interactions do not necessarily take place between single variables, but may occur among groups, or "ensembles", of variables. In this study we establish a principled framework for Granger causality in the context of causal interactions among two or more multivariate sets of variables. Building on Geweke's seminal 1982 work, we offer new justifications for one particular form of multivariate Granger causality based on the generalized variances of residual errors. Taken together, our results support a comprehensive and theoretically consistent extension of Granger causality to the multivariate case. Treated individually, they highlight several specific advantages of the generalized variance measure, which we illustrate using applications in neuroscience as an example. We further show how the measure can be used to define "partial" Granger causality in the multivariate context and we also motivate reformulations of "causal density" and "Granger autonomy". Our results are directly applicable to experimental data and promise to reveal new types of functional relations in complex systems, neural and otherwise.Comment: added 1 reference, minor change to discussion, typos corrected; 28 pages, 3 figures, 1 table, LaTe

1-year mortality following contrast-induced nephropathy

Objective: The aim of this study was to determine the 1-year mortality risk subsequent to Contrast-Induced Nephropathy (CIN) following CECT imaging, relative to other well-recognized predictors of mortality. Methods: We followed a prospective, consecutive cohort of ambulatory patients who received intravenous contrast for CECT for the outcome of death from any cause within 1 year. In a multivariate analysis, we compared CIN with other predictors of mortality: active malignancy, coronary artery disease (CAD), congestive heart failure (CHF) and age ≥70 years. Anticipating that terminal cancers would account for the majority of deaths in this population, we also analyzed the subset of patients without an active malignancy at the time of enrollment. Results: We followed 633 patients and 46 died (7%, 95%CI: 5-9%) within 1 year. The incidence of CIN was 11% (95%CI: 8-14%). Active malignancy (HR 9.2, 95%CI: 5.1-16.8), CIN (HR 2.4, 95%CI: 1.3-4.6), CHF (HR 2.1, 95%CI: 1.0-4.2), CAD (HR 2.2, 95%CI: 1.0-5.5) and age ≥70 years (HR 1.8, 95%CI: 1.0-3.8) were significant predictors of all-cause mortality. Among patients without active malignancies, the mortality rate was 4% (25/580, 95%CI: 3-6%) and CIN (HR 4.0, 95%CI: 1.7-9.6) and age ≥70 years (HR 3.7, 95%CI: 1.4-9.7) were significantly associated with death, whereas CAD (HR 2.5, 95%CI: 0.8-7.7) and CHF (HR 1.8, 95%CI: 0.6-5.3) were not. Conclusions: The development of CIN following CECT is associated with an increased likelihood of death at 1 year among patients with and without active malignancies, comparable to CAD, CHF and advanced age