Breaking down automaticity: Case ambiguity and the shift to reflective approaches in clinical reasoning

Context: Two modes of case processing have been shown to underlie diagnostic judgements: analytical and non-analytical reasoning. An optimal form of clinical reasoning is suggested to combine both modes. Conditions leading doctors to shift from the usual mode of non-analytical reasoning to reflective reasoning have not been identified. This paper reports a study aimed at exploring these conditions by investigating the effects of ambiguity of clinical cases on clinical reasoning. Methods: Participants were 16 internal medicine residents in the Brazilian state of Ceará. They were asked to diagnose 20 clinical cases and recall case information. The independent variable was the degree of ambiguity of clinical cases, with 2 levels: straightforward (i.e. non-ambiguous) and ambiguous. Dependent variables were processing time, diagnostic accuracy and proposition per category recalled. Data were analysed using a repeated measures design. Results: Participants processed straightforward cases faster and more accurately than ambiguous ones. The proportion of text propositions recalled was significantly lower (t[15] = 2.29, P = 0.037) in ambiguous cases, and an interaction effect between case version and proposition category was also found (F[5, 75] = 4.52, P = 0.001, d = 0.232, observed power = 0.962). Furthermore, participants recalled significantly more literal propositions from the ambiguous cases than from the straightforward cases (t[15] = 2.28, P = 0.037). Conclusions: Ambiguity of clinical cases was shown to lead residents to switch from automatic to reflective reasoning, as indicated by longer processing time, and more literal propositions recalled in ambiguous cases

Development of a Sandwich ELISA to Measure Exposure to Occupational Cow Hair Allergens

Background: Cow hair and dander are important inducers of occupational allergies in cattle-exposed farmers. To estimate allergen exposure in farming environments, a sensitive enzyme immunoassay was developed to measure cow hair allergens. Methods: A sandwich ELISA was developed using polyclonal rabbit antibodies against a mixture of hair extracts from different cattle breeds. To assess the specificity of the assay, extracts from other mammalian epithelia, mites, molds and grains were tested. To validate the new assay, cow hair allergens were measured in passive airborne dust samples from the stables and homes of farmers. Dust was collected with electrostatic dust fall collectors (EDCs). Results: The sandwich ELISA was found to be very sensitive (detection limit: 0.1 ng/ml) and highly reproducible, demonstrating intra-and interassay coefficients of variation of 4 and 10%, respectively. The assay showed no reactivity with mites, molds and grains, but some cross-reactivity with other mammalian epithelia, with the strongest reaction with goat. Using EDCs for dust sampling, high concentrations of bovine allergens were measured in cow stables (4,760-559,400 mu g/m(2)). In addition, bovine allergens were detected in all areas of cattle farmer dwellings. A large variation was found between individual samples (0.3-900 mu g/m(2)) and significantly higher values were discovered in changing rooms. Conclusion: The ELISA developed for the detection of cow hair proteins is a useful tool for allergen quantification in occupational and home environments. Based on its low detection limit, this test is sensitive enough to detect allergens in passive airborne dust. Copyright (C) 2011 S. Karger AG, Base

Chemotherapy-Response Monitoring of Breast Cancer Patients Using Quantitative Ultrasound-Based Intra-Tumour Heterogeneities

© 2017 The Author(s). Anti-cancer therapies including chemotherapy aim to induce tumour cell death. Cell death introduces alterations in cell morphology and tissue micro-structures that cause measurable changes in tissue echogenicity. This study investigated the effectiveness of quantitative ultrasound (QUS) parametric imaging to characterize intra-tumour heterogeneity and monitor the pathological response of breast cancer to chemotherapy in a large cohort of patients (n = 100). Results demonstrated that QUS imaging can non-invasively monitor pathological response and outcome of breast cancer patients to chemotherapy early following treatment initiation. Specifically, QUS biomarkers quantifying spatial heterogeneities in size, concentration and spacing of acoustic scatterers could predict treatment responses of patients with cross-validated accuracies of 82 ± 0.7%, 86 ± 0.7% and 85 ± 0.9% and areas under the receiver operating characteristic (ROC) curve of 0.75 ± 0.1, 0.80 ± 0.1 and 0.89 ± 0.1 at 1, 4 and 8 weeks after the start of treatment, respectively. The patients classified as responders and non-responders using QUS biomarkers demonstrated significantly different survivals, in good agreement with clinical and pathological endpoints. The results form a basis for using early predictive information on survival-linked patient response to facilitate adapting standard anti-cancer treatments on an individual patient basis

Phenomenological Consequences of sub-leading Terms in See-Saw Formulas

Several aspects of next-to-leading (NLO) order corrections to see-saw formulas are discussed and phenomenologically relevant situations are identified. We generalize the formalism to calculate the NLO terms developed for the type I see-saw to variants like the inverse, double or linear see-saw, i.e., to cases in which more than two mass scales are present. In the standard type I case with very heavy fermion singlets the sub-leading terms are negligible. However, effects in the percent regime are possible when sub-matrices of the complete neutral fermion mass matrix obey a moderate hierarchy, e.g. weak scale and TeV scale. Examples are cancellations of large terms leading to small neutrino masses, or inverse see-saw scenarios. We furthermore identify situations in which no NLO corrections to certain observables arise, namely for mu-tau symmetry and cases with a vanishing neutrino mass. Finally, we emphasize that the unavoidable unitarity violation in see-saw scenarios with extra fermions can be calculated with the formalism in a straightforward manner.Comment: 22 pages, matches published versio

Pathways to new drug discovery in neuropsychiatry

There is currently a crisis in drug discovery for neuropsychiatric disorders, with a profound, yet unexpected drought in new drug development across the spectrum. In this commentary, the sources of this dilemma and potential avenues to redress the issue are explored. These include a critical review of diagnostic issues and of selection of participants for clinical trials, and the mechanisms for identifying new drugs and new drug targets. Historically, the vast majority of agents have been discovered serendipitously or have been modifications of existing agents. Serendipitous discoveries, based on astute clinical observation or data mining, remain a valid option, as is illustrated by the suggestion in the paper by Wahlqvist and colleagues that treatment with sulfonylurea and metformin reduces the risk of affective disorder. However, the identification of agents targeting disorder-related biomarkers is currently proving particularly fruitful. There is considerable hope for genetics as a purist, pathophysiologically valid pathway to drug discovery; however, it is unclear whether the science is ready to meet this promise. Fruitful paradigms will require a break from the orthodoxy, and creativity and risk may well be the fingerprints of success

Color & Weak triplet scalars, the dimuon asymmetry in BsB_s decay, the top forward-backward asymmetry, and the CDF dijet excess

The new physics required to explain the anomalies recently reported by the D0 and CDF collaborations, namely the top forward-backward asymmetry (FBA), the like-sign dimuon charge asymmetry in semileptonic b decay, and the CDF dijet excess, has to feature an amount of flavor symmetry in order to satisfy the severe constrains arising from flavor violation. In this paper we show that, once baryon number conservation is imposed, color & weak triplet scalars with hypercharge $Y=1/3$ can feature the required flavor structure as a consequence of standard model gauge invariance. The color & weak triplet model can simultaneously explain the top FBA and the dimuon charge asymmetry or the dimuon charge asymmetry and the CDF dijet excess. However, the CDF dijet excess appears to be incompatible with the top FBA in the minimal framework. Our model for the dimuon asymmetry predicts the observed pattern $h_d\ll h_s$ in the region of parameter space required to explain the top FBA, whereas our model for the CDF dijet anomaly is characterized by the absence of beyond the SM b-quark jets in the excess region. Compatibility of the color & weak triplet with the electroweak constraints is also discussed. We show that a Higgs boson mass exceeding the LEP bound is typically favored in this scenario, and that both Higgs production and decay can be significantly altered by the triplet. The most promising collider signature is found if the splitting among the components of the triplet is of weak scale magnitude.Comment: references added, published versio

Neutralino versus axion/axino cold dark matter in the 19 parameter SUGRA model

We calculate the relic abundance of thermally produced neutralino cold dark matter in the general 19 parameter supergravity (SUGRA-19) model. A scan over GUT scale parameters reveals that models with a bino-like neutralino typically give rise to a dark matter density \Omega_{\tz_1}h^2\sim 1-1000, i.e. between 1 and 4 orders of magnitude higher than the measured value. Models with higgsino or wino cold dark matter can yield the correct relic density, but mainly for neutralino masses around 700-1300 GeV. Models with mixed bino-wino or bino-higgsino CDM, or models with dominant co-annihilation or A-resonance annihilation can yield the correct abundance, but such cases are extremely hard to generate using a general scan over GUT scale parameters; this is indicative of high fine-tuning of the relic abundance in these cases. Requiring that m_{\tz_1}\alt 500 GeV (as a rough naturalness requirement) gives rise to a minimal probably dip in parameter space at the measured CDM abundance. For comparison, we also scan over mSUGRA space with four free parameters. Finally, we investigate the Peccei-Quinn augmented MSSM with mixed axion/axino cold dark matter. In this case, the relic abundance agrees more naturally with the measured value. In light of our cumulative results, we conclude that future axion searches should probe much more broadly in axion mass, and deeper into the axion coupling.Comment: 23 pages including 17 .eps figure

Study of the Falling Friction Effect on Rolling Contact Parameters

[EN] The existence of a wheel rail friction coefficient that depends on the slip velocity has been associated in the literature with important railway problems like the curving squeal and certain corrugation problems in rails. Rolling contact models that take into account this effect were carried out through the so-called Exact Theories adopting an exact elastic model of the solids in contact, and Simplified Theories which assume simplified elastic models such as Winkler. The former ones, based on Kalker s Variational Theory, give rise to numerical problems; the latter ones need to adopt hypotheses that significantly deviate from actual conditions, leading to unrealistic solutions of the contact problem. In this paper, a methodology based on Kalker s Variational Theory is presented, in which a local slip velocity-dependent friction law is considered. A formulation to get steady-state conditions of rolling contact by means of regularisation of the Coulomb s law is proposed. The model allows establishing relationships in order to estimate the global properties (creepage velocities vs. total longitudinal forces) through local properties (local slip velocity vs. coefficient of friction) or vice versa. The proposed model shows a good agreement with experimental tests while solving the numerical problems previously mentioned.The authors acknowledge the financial contribution of the Spanish Ministry of Economy and Competitiveness through the Project TRA2013-45596-C2-1-R.Giner Navarro, J.; Baeza González, LM.; Vila Tortosa, MP.; Alonso Pazos, A. (2017). Study of the Falling Friction Effect on Rolling Contact Parameters. Tribology Letters. 65(1). https://doi.org/10.1007/s11249-016-0810-8S651Grassie, S.L., Elkins, J.A.: Rail corrugation on North American transit systems. Veh. Syst. Dyn. 28, 5–17 (1998)Hsu, S.S., Huang, Z., Iwnicki, S.D., Thompson, D.J., Jones, C.J.C., Xie, G., Allen, P.D.: Experimental and theoretical investigation of railway wheel squeal. Proc. Inst. Mech. Eng. F J. Rail Rapid Transit 221, 59–73 (2007)Kalker, J.J.: Three-Dimensional Elastic Bodies in Rolling Contact. Kluwer, Dordrecht (1990)Polach, O.: Influence of locomotive tractive effort on the forces between wheel and rail. Veh. Syst. Dyn. 35, 7–22 (2001)Giménez, J.G., Alonso, A., Gómez, E.: Introduction of a friction coefficient dependent on the slip in the FastSim algorithm. Veh. Syst. Dyn. 43, 233–244 (2005)Baeza, L., Vila, P., Roda, A., Fayos, J.: Prediction of corrugation in rails using a non-stationary wheel–rail contact model. Wear 265, 1156–1162 (2008)Vollebregt, E.A.H., Schuttelaars, H.M.: Quasi-static analysis of two-dimensional rolling contact with slip-velocity dependent friction. J. Sound Vib. 331, 2141–2155 (2012)Avlonitis, M., Kalaitzidou, K., Streator, J.: Investigation of friction statics and real contact area by means a modified OFC model. Tribol. Int. 69, 168–175 (2014)Berger, E.J., Mackin, T.J.: On the walking stick–slip problem. Tribol. Int. 75, 51–60 (2014)Alonso, A., Guiral, A., Baeza, B., Iwnicki, S.D.: Wheel–rail contact: experimental study of the creep forces–creepage relationships. Veh. Syst. Dyn. 52(S1), 469–487 (2014)Spiryagin, M., Polach, O., Cole, C.: Creep force modelling for rail traction vehicles based on the Fastsim algorithm. Veh. Syst. Dyn. 51, 1765–1783 (2013)Vollebregt, E.A.H.: Numerical modeling of measured railway creep versus creep-force curves with CONTACT. Wear 314, 87–95 (2014)Kalker, J.J.: On the Rolling Contact of Two Elastic Bodies in the Presence of Dry Friction. PhD Thesis, Technical University of Delft (Holland) (1967)Baeza, L., Fuenmayor, F.J., Carballeira, J., Roda, A.: Influence of the wheel–rail contact instationary process on contact parameters. J. Strain Anal. Eng. 42, 377–387 (2007)Le Rouzic, J., Le Bot, A., Perret-Liaudet, J., Guibert, M., Rusanov, A., Douminge, L., Bretagnol, F., Mazuyer, D.: Friction-induced vibration by Stribeck’s law: application to wiper blade squeal noise. Tribol. Lett. 49, 563–572 (2013)Rabinowicz, E.: The nature of the static and kinetic coefficients of friction. J. Appl. Phys. 22, 1373–1379 (1951)Carter, F.W.: On the action of locomotive driving wheel. Proc. R. Soc. Lon. Ser. A 112, 151–157 (1926)Kalker, J.J.: A fast algorithm for the simplified theory of rolling contact. Veh. Syst. Dyn. 11, 1–13 (1982