222 research outputs found

    Uncovering latent singularities from multifractal scaling laws in mixed asymptotic regime. Application to turbulence

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    In this paper we revisit an idea originally proposed by Mandelbrot about the possibility to observe ``negative dimensions'' in random multifractals. For that purpose, we define a new way to study scaling where the observation scale τ\tau and the total sample length LL are respectively going to zero and to infinity. This ``mixed'' asymptotic regime is parametrized by an exponent χ\chi that corresponds to Mandelbrot ``supersampling exponent''. In order to study the scaling exponents in the mixed regime, we use a formalism introduced in the context of the physics of disordered systems relying upon traveling wave solutions of some non-linear iteration equation. Within our approach, we show that for random multiplicative cascade models, the parameter χ\chi can be interpreted as a negative dimension and, as anticipated by Mandelbrot, allows one to uncover the ``hidden'' negative part of the singularity spectrum, corresponding to ``latent'' singularities. We illustrate our purpose on synthetic cascade models. When applied to turbulence data, this formalism allows us to distinguish two popular phenomenological models of dissipation intermittency: We show that the mixed scaling exponents agree with a log-normal model and not with log-Poisson statistics.Comment: 4 pages, 3 figure

    Counting function fluctuations and extreme value threshold in multifractal patterns: the case study of an ideal 1/f1/f noise

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    To understand the sample-to-sample fluctuations in disorder-generated multifractal patterns we investigate analytically as well as numerically the statistics of high values of the simplest model - the ideal periodic 1/f1/f Gaussian noise. By employing the thermodynamic formalism we predict the characteristic scale and the precise scaling form of the distribution of number of points above a given level. We demonstrate that the powerlaw forward tail of the probability density, with exponent controlled by the level, results in an important difference between the mean and the typical values of the counting function. This can be further used to determine the typical threshold xmx_m of extreme values in the pattern which turns out to be given by xm(typ)=2clnlnM/lnMx_m^{(typ)}=2-c\ln{\ln{M}}/\ln{M} with c=3/2c=3/2. Such observation provides a rather compelling explanation of the mechanism behind universality of cc. Revealed mechanisms are conjectured to retain their qualitative validity for a broad class of disorder-generated multifractal fields. In particular, we predict that the typical value of the maximum pmaxp_{max} of intensity is to be given by lnpmax=αlnM+32f(α)lnlnM+O(1)-\ln{p_{max}} = \alpha_{-}\ln{M} + \frac{3}{2f'(\alpha_{-})}\ln{\ln{M}} + O(1), where f(α)f(\alpha) is the corresponding singularity spectrum vanishing at α=α>0\alpha=\alpha_{-}>0. For the 1/f1/f noise we also derive exact as well as well-controlled approximate formulas for the mean and the variance of the counting function without recourse to the thermodynamic formalism.Comment: 28 pages; 7 figures, published version with a few misprints corrected, editing done and references adde

    Modelling the propagation of adult male muscle dysmorphia in Spain: economic, emotional and social drivers

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    This is an author's accepted manuscript of an article published in: “Applied Economics"; Volume 47, Issue 12, 2015; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1080/00036846.2013.870657Males aged over 40 do more gym practice to improve their body image as a way of reinforcing their personal self-esteem and sexual appeal. Cases when self-image becomes an obsession may result in a body dysmorphic disorder named ‘muscle dysmorphia’ (MD). The combination of psychological, environmental and biological drivers determines the appearance and development of this disorder. In this article, we developed a discrete population mathematical model to forecast the rate of prevalence of males who are noncompetitive bodybuilders at risk of suffering MD in Spain in forthcoming years. Economic, emotional, sociological and psychological motivations were taken into account to quantify the dynamic behaviour of Spanish noncompetitive bodybuilders. The impact of the unemployment is reflected in the construction of two coefficients, αu and α21, which explain subpopulation transits due to the economy. Sociological influences, such as human herding and social propagation, were also considered. Our results predict an increase in Spanish noncompetitive bodybuilders suffering MD from 1% in 2011 to around 11% in 2015. Our model can be applied to any other western country where data are available and to another study period when the hypotheses are applicable.De La Poza, E.; Jódar Sánchez, LA.; Alkasadi, M. (2015). Modelling the propagation of adult male muscle dysmorphia in Spain: economic, emotional and social drivers. Applied Economics. 47(12):1159-1169. https://doi.org/10.1080/00036846.2013.870657S115911694712Blashfield, R. K., Sprock, J., & Fuller, A. K. (1990). Suggested guidelines for including or excluding categories in the DSM-IV. Comprehensive Psychiatry, 31(1), 15-19. doi:10.1016/0010-440x(90)90049-xBoyda, D., & Shevlin, M. 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Frequent dieting among adolescents: psychosocial and health behavior correlates. American Journal of Public Health, 85(5), 695-701. doi:10.2105/ajph.85.5.695García, I., Jódar, L., Merello, P., & Santonja, F.-J. (2011). A discrete mathematical model for addictive buying: Predicting the affected population evolution. Mathematical and Computer Modelling, 54(7-8), 1634-1637. doi:10.1016/j.mcm.2010.12.012González-Martí, I., Bustos, J. G. F., Jordán, O. R. C., & Mayville, S. B. (2012). Validation of a Spanish version of the Muscle Appearance Satisfaction Scale: Escala de Satisfacción Muscular. Body Image, 9(4), 517-523. doi:10.1016/j.bodyim.2012.05.002Greenberg, J. L., Markowitz, S., Petronko, M. R., Taylor, C. E., Wilhelm, S., & Wilson, G. T. (2010). Cognitive-Behavioral Therapy for Adolescent Body Dysmorphic Disorder. Cognitive and Behavioral Practice, 17(3), 248-258. doi:10.1016/j.cbpra.2010.02.002Hildebrandt, T., Schlundt, D., Langenbucher, J., & Chung, T. (2006). Presence of muscle dysmorphia symptomology among male weightlifters. Comprehensive Psychiatry, 47(2), 127-135. doi:10.1016/j.comppsych.2005.06.001Hitzeroth, V., Wessels, C., Zungu-Dirwayi, N., Oosthuizen, P., & Stein, D. J. (2001). Muscle dysmorphia: A South African sample. Psychiatry and Clinical Neurosciences, 55(5), 521-523. doi:10.1046/j.1440-1819.2001.00899.xHONEKOPP, J., RUDOLPH, U., BEIER, L., LIEBERT, A., & MULLER, C. (2007). Physical attractiveness of face and body as indicators of physical fitness in men. Evolution and Human Behavior, 28(2), 106-111. doi:10.1016/j.evolhumbehav.2006.09.001Humphreys, B. R., & Ruseski, J. E. (2011). An Economic Analysis of Participation and Time Spent in Physical Activity. The B.E. Journal of Economic Analysis & Policy, 11(1). doi:10.2202/1935-1682.2522Kanayama, G. (2006). Body Image and Attitudes Toward Male Roles in Anabolic-Androgenic Steroid Users. 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    Can teaching agenda-setting skills to physicians improve clinical interaction quality? A controlled intervention

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    <p>Abstract</p> <p>Background</p> <p>Physicians and medical educators have repeatedly acknowledged the inadequacy of communication skills training in the medical school curriculum and opportunities to improve these skills in practice. This study of a controlled intervention evaluates the effect of teaching practicing physicians the skill of "agenda-setting" on patients' experiences with care. The agenda-setting intervention aimed to engage clinicians in the practice of initiating patient encounters by eliciting the full set of concerns from the patient's perspective and using that information to prioritize and negotiate which clinical issues should most appropriately be dealt with and which (if any) should be deferred to a subsequent visit.</p> <p>Methods</p> <p>Ten physicians from a large physician organization in California with baseline patient survey scores below the statewide 25th percentile participated in the agenda-setting intervention. Eleven physicians matched on baseline scores, geography, specialty, and practice size were selected as controls. Changes in survey summary scores from pre- and post-intervention surveys were compared between the two groups. Multilevel regression models that accounted for the clustering of patients within physicians and controlled for respondent characteristics were used to examine the effect of the intervention on survey scale scores.</p> <p>Results</p> <p>There was statistically significant improvement in intervention physicians' ability to "explain things in a way that was easy to understand" (p = 0.02) and marginally significant improvement in the overall quality of physician-patient interactions (p = 0.08) compared to control group physicians. Changes in patients' experiences with organizational access, care coordination, and office staff interactions did not differ by experimental group.</p> <p>Conclusion</p> <p>A simple and modest behavioral training for practicing physicians has potential to positively affect physician-patient relationship interaction quality. It will be important to evaluate the effect of more extensive trainings, including those that work with physicians on a broader set of communication techniques.</p

    Precision measurements of differential cross sections and analyzing powers in elastic deuteron-deuteron scattering at 65 MeV/nucleon

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    We present measurements of differential cross sections and analyzing powers for the elastic 2H(d, d)d scat-tering process. The data were obtained using a 130 MeV polarized deuteron beam. Cross sections and spin observ-ables of the elastic scattering process were measured at the AGOR facility at KVI using two independent setups, namely BINA and BBS. The data harvest at setups are in excellent agreement with each other and allowed us to carry out a thor-ough systematic analysis to provide the most accurate data in elastic deuteron-deuteron scattering at intermediate energies. The results can be used to confront upcoming state-of-the-art calculations in the four-nucleon scattering domain, and will, thereby, provide further insights in the dynamics of three-and four-nucleon forces in few-nucleon systems

    COVID-19 severity and mortality in patients with chronic lymphocytic leukemia: a joint study by ERIC, the European Research Initiative on CLL, and CLL Campus

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    Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79–7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p &lt; 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency

    Phase I clinical trial in healthy adults of a nasal vaccine candidate containing recombinant hepatitis B surface and core antigens

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    SummaryBackgroundThe nasal vaccine candidate (NASVAC), comprising hepatitis B virus (HBV) surface (HBsAg) and core antigens (HBcAg), has been shown to be highly immunogenic in animal models.MethodsA phase I double-blinded, placebo-controlled randomized clinical trial was carried out in 19 healthy male adults with no serologic markers of immunity/infection to HBV. This study was aimed at exploring the safety and immunogenic profile of nasal co-administration of both HBV recombinant antigens. The trial was performed according to Good Clinical Practice guidelines. Participants ranged in age from 18 to 45 years and were randomly allocated to receive a mixture of 50μg HBsAg and 50μg HBcAg or 0.9% physiologic saline solution, as a placebo, via nasal spray in a five-dose schedule at 0, 7, 15, 30, and 60 days. A total volume of 0.5ml was administered in two dosages of 125μl per nostril. Adverse events were actively recorded 1h, 6h, 12h, 24h, 48h, 72h, 7 days and 30 days after each dose. Anti-HBs and anti-HBc titers were evaluated using corresponding ELISA kits at days 30 and 90.ResultsThe vaccine candidate was safe and well tolerated. Adverse reactions included sneezing (34.1%), rhinorrhea (12.2%), nasal stuffiness (9.8%), palate itching (9.8%), headache (9.8%), and general malaise (7.3%). These reactions were all self-limiting and mild in intensity. No severe or unexpected events were recorded during the trial. The vaccine elicited anti-HBc seroconversion in 100% of subjects as early as day 30 of the immunization schedule, while a seroprotective anti-HBs titer (≥10IU/l) was at a maximum at day 90 (75%). All subjects in the placebo group remained seronegative during the trial.ConclusionThe HBsAg–HBcAg vaccine candidate was safe, well tolerated and immunogenic in this phase I study in healthy adults. To our knowledge, this is the first demonstration of safety and immunogenicity for a nasal vaccine candidate comprising HBV antigens
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