Spiral Defect Chaos in Large Aspect Ratio Rayleigh-Benard Convection

We report experiments on convection patterns in a cylindrical cell with a large aspect ratio. The fluid had a Prandtl number of approximately 1. We observed a chaotic pattern consisting of many rotating spirals and other defects in the parameter range where theory predicts that steady straight rolls should be stable. The correlation length of the pattern decreased rapidly with increasing control parameter so that the size of a correlated area became much smaller than the area of the cell. This suggests that the chaotic behavior is intrinsic to large aspect ratio geometries.Comment: Preprint of experimental paper submitted to Phys. Rev. Lett. May 12 1993. Text is preceeded by many TeX macros. Figures 1 and 2 are rather lon

Thermally Induced Fluctuations Below the Onset of Rayleigh-B\'enard Convection

We report quantitative experimental results for the intensity of noise-induced fluctuations below the critical temperature difference $\Delta T_c$ for Rayleigh-B\'enard convection. The structure factor of the fluctuating convection rolls is consistent with the expected rotational invariance of the system. In agreement with predictions based on stochastic hydrodynamic equations, the fluctuation intensity is found to be proportional to $1/\sqrt{-\epsilon}$ where $\epsilon \equiv \Delta T / \Delta T_c -1$. The noise power necessary to explain the measurements agrees with the prediction for thermal noise. (WAC95-1)Comment: 13 pages of text and 4 Figures in a tar-compressed and uuencoded file (using uufiles package). Detailed instructions of unpacking are include

Orbifold projection in supersymmetric QCD at N_f\leq N_c

Supersymmetric orbifold projection of N=1 SQCD with relatively small number of flavors (not larger than the number of colors) is considered. The purpose is to check whether orbifolding commutes with the infrared limit. On the one hand, one considers the orbifold projection of SQCD and obtains the low-energy description of the resulting theory. On the other hand, one starts with the low-energy effective theory of the original SQCD, and only then perfoms orbifolding. It is shown that at finite N_c the two low-energy theories obtained in these ways are different. However, in the case of stabilized run-away vacuum these two theories are shown to coincide in the large N_c limit. In the case of quantum modified moduli space, topological solitons carrying baryonic charges are present in the orbifolded low-energy theory. These solitons may restore the correspondence between the two theories provided that the soliton mass tends to zero in the large N_c limit.Comment: 10 pages; misprint corrected, reference adde

Poisson-Hopf limit of quantum algebras

The Poisson-Hopf analogue of an arbitrary quantum algebra U_z(g) is constructed by introducing a one-parameter family of quantizations U_{z,h}(g) depending explicitly on h and by taking the appropriate h -> 0 limit. The q-Poisson analogues of the su(2) algebra are discussed and the novel su_q^P (3) case is introduced. The q-Serre relations are also extended to the Poisson limit. This approach opens the perspective for possible applications of higher rank q-deformed Hopf algebras in semiclassical contexts.Comment: 13 pages, no figure

Influence of through-flow on linear pattern formation properties in binary mixture convection

We investigate how a horizontal plane Poiseuille shear flow changes linear convection properties in binary fluid layers heated from below. The full linear field equations are solved with a shooting method for realistic top and bottom boundary conditions. Through-flow induced changes of the bifurcation thresholds (stability boundaries) for different types of convective solutions are deter- mined in the control parameter space spanned by Rayleigh number, Soret coupling (positive as well as negative), and through-flow Reynolds number. We elucidate the through-flow induced lifting of the Hopf symmetry degeneracy of left and right traveling waves in mixtures with negative Soret coupling. Finally we determine with a saddle point analysis of the complex dispersion relation of the field equations over the complex wave number plane the borders between absolute and convective instabilities for different types of perturbations in comparison with the appropriate Ginzburg-Landau amplitude equation approximation. PACS:47.20.-k,47.20.Bp, 47.15.-x,47.54.+rComment: 19 pages, 15 Postscript figure

Lived Experiences of Educators Engaged in Continuing Professional Development in the New Normal: Insights from Seven Countries

This study focused on exploring and capturing the essence and meaning of the lived experiences of educators engaged in continuing professional development in the new normal. The study followed a qualitative research design and used the transcendental phenomenological processes. Based from the testimonies gathered from the participants from seven different countries- Philippines, USA, Panama, Peru, Pakistan, Nigeria, and Morocco they revealed that as a result of the Continuing Professional Development during pandemic, they have manifested adaptability and innovation to meet the demands of the current situation. With the force transition from face to face interaction to remote learning, they have tried their best to maintain a balance of digital and life skills. Participants also engaged in CPD in order to achieve creativity and resourcefulness to deliver and meet students’ quality learning amidst pandemic. They also considered as blessings and great opportunity the connection and collaboration established with educators around the world during this time of Covid-19. They also achieved the passion for ever-learning mindset and satisfaction through CPD. Participants expressed that mindfulness and wellbeing of teachers should be set as priorities for their engagement to CPD in the new normal. The researcher recommends that the policy makers review and revisit their program for CPD training of the teachers during this period. Heads of the education sectors may also benchmark the CPD Training plan of this study and conduct needs analysis to provide the most appropriate trainings for the teachers based on their needs, skills and interests

Association between faecal pH and fat absorption in children with cystic fibrosis on a controlled diet and enzyme supplements dose

[EN] Background Despite treatment with pancreatic enzyme replacement therapy (PERT), patients with cystic fibrosis (CF) can still suffer from fat malabsorption. A cause could be low intestinal pH disabling PERT. The aim of this study was to assess the association between faecal pH (as intestinal pH surrogate) and coefficient of fat absorption (CFA). Additionally, faecal free fatty acids (FFAs) were quantified to determine the amount of digested, but unabsorbed fat. Methods In a 24-h pilot study, CF patients followed a standardised diet with fixed PERT doses, corresponding to theoretical optimal doses determined by an in vitro digestion model. Study variables were faecal pH, fat and FFA excretion, CFA and transit time. Linear mixed regression models were applied to explore associations. Results In 43 patients, median (1st, 3rd quartile) faecal pH and CFA were 6.1% (5.8, 6.4) and 90% (84, 94), and they were positively associated (p < 0.001). An inverse relationship was found between faecal pH and total fat excretion (p < 0.01), as well as total FFA (p = 0.048). Higher faecal pH was associated with longer intestinal transit time (p = 0.049) and the use of proton pump inhibitors (p = 0.009). Conclusions Although the clinical significance of faecal pH is not fully defined, its usefulness as a surrogate biomarker for intestinal pH should be further explored. Impact Faecal pH is a physiological parameter that may be related to intestinal pH and may provide important physiopathological information on CF-related pancreatic insufficiency. Faecal pH is correlated with fat absorption, and this may explain why pancreatic enzyme replacement therapy is not effective in all patients with malabsorption related to CF. Use of proton pump inhibitors is associated to higher values of faecal pH. Faecal pH could be used as a surrogate biomarker to routinely monitor the efficacy of pancreatic enzyme replacement therapy in clinical practice. Strategies to increase intestinal pH in children with cystic fibrosis should be targeted.We acknowledge the support of the MyCyFAPP Project consortium. We especially thank the participation and the effort of the patients involved in the study and their families. This work was fully funded by the European Union and the Horizon 2020 Research and Innovation Framework Programme (PHC-26-2014 call Self management of health and disease: citizen engagement and mHealth) under grant number 643806.Calvo-Lerma, J.; Roca-Llorens, M.; Boon, M.; Colombo, C.; De Koning, B.; Fornés-Ferrer, V.; Masip, E.... (2021). Association between faecal pH and fat absorption in children with cystic fibrosis on a controlled diet and enzyme supplements dose. Pediatric Research. 89(1):205-210. https://doi.org/10.1038/s41390-020-0860-3S205210891Turck, D. et al. ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with cystic fibrosis. Clin. Nutr. 35, 557–577 (2016).Borowitz, D., Baker, R. 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Physical–chemical behavior of dietary and biliary lipids during intestinal digestion and absorption. 2. Phase analysis and aggregation states of luminal lipids during duodenal fat digestionin healthy adult human beings. Biochemistry 29, 2041–2056 (1990).Calvo-Lerma, J. et al. A first approach for an evidence-based in vitro method to adjust pancreatic enzyme replacement therapy in cystic fibrosis. PLoS ONE 14, e0212459 (2019).Aburub, A. Comparison of pH and motility of the small intestine of healthy subjects and patients with symptomatic constipation using the wireless motility capsule. Int. J. Pharm. 544, 158–164 (2018).Calvo-Lerma, J. et al. Innovative approach for self-management and social welfare of children with cystic fibrosis in Europe: development, validation and implementation of an mHealth tool (MyCyFAPP). Br. Med. J. Open. 7, e014931 (2017).Calvo-Lerma, J. et al. Clinical validation of an evidence-based method to adjust pancreatic enzyme replacement therapy through a prospective interventional study in paediatric patients with cystitic fibrosis. PLoS ONE 14, e0213216 (2019).Koumantakls, G. & Radciltf, F. J. Estimating fat in feces by near-infrared reflectance spectroscopy. Clin. Chem. 33, 502–506 (1987).Rivero-Marcotegui, A. et al. Water, fat, nitrogen, and sugar content in feces: reference intervals in children. Clin. Chem. 44, 1540–1544 (1998).Korpi-Steiner, N. L. et al. Comparative analysis of fecal fat quantitation via nuclear magnetic resonance spectroscopy (1H NMR) and gravimetry. Clin. Chim. Acta 400, 33–36 (2009).Dorsey, J. et al. Fat malabsorption in cystic fibrosis: comparison of quantitative fat assay and a novel assay using fecal lauric/behenic acid. J. Pediatr. Gastroenterol. Nutr. 50, 441–446 (2010).Proesmans, M. & De Boeck, K. 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Fat digestibility in meat products: influence of food structure and gastrointestinal conditions. Int. J. Food Sci. Nutr. 70, 530–539 (2019).Regan, P. T. et al. Reduced intraluminal bile acid concentrations and fat maldigestion in pancreatic insufficiency: correction by treatment. Gastroenterology 7, 285–289 (1979).Fallingborg, J. et al. pH‐profile and regional transit times of the normal gut measured by a radiotelemetry device. Aliment. Phamacol. Ther. 3, 605–614 (1989).Fallingborg, J. Intraluminal pH of the human gastrointestinal tract. Dan. Med Bull. 46, 183–196 (1999).Calvo-Lerma, J. et al. In vitro digestion models to assess lipolysis: the impact of the simulated conditions for gastrointestinal pH, bile salts and digestion fluids. Food Res. Int. 125, 108511 (2019).Kalantzi, L. Characterization of the human upper gastrointestinal contents under conditions simulating bioavailability/bioequivalence studies. Pharm. Res. 23, 165–176 (2006).Zelles, L. & Bai, Q. Y. 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Superdeformation in the Doubly Magic Nucleus 40Ca

A rotational band with seven gamma -ray transitions between states with spin 2 (h) over bar and 16 (h) over bar has been observed in the doubly magic, self-conjugate nucleus Ca-40(20)20. The measured transition quadrupole moment of 1.80(-0.29)(+0.39)eb indicates a superdeformed shape with a deformation beta (2) = 0.59(-0.07)(+0.11). The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation

Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure