Experimental growth law for bubbles in a "wet" 3D liquid foam

We used X-ray tomography to characterize the geometry of all bubbles in a liquid foam of average liquid fraction $\phi_l\approx 17$ and to follow their evolution, measuring the normalized growth rate $\mathcal{G}=V^{-{1/3}}\frac{dV} {dt}$ for 7000 bubbles. While $\mathcal{G}$ does not depend only on the number of faces of a bubble, its average over $f-$faced bubbles scales as $G_f\sim f-f_0$ for large $f$s at all times. We discuss the dispersion of $\mathcal{G}$ and the influence of $V$ on $\mathcal{G}$.Comment: 10 pages, submitted to PR

Computer-Assisted Proofs of Some Identities for Bessel Functions of Fractional Order

We employ computer algebra algorithms to prove a collection of identities involving Bessel functions with half-integer orders and other special functions. These identities appear in the famous Handbook of Mathematical Functions, as well as in its successor, the DLMF, but their proofs were lost. We use generating functions and symbolic summation techniques to produce new proofs for them.Comment: Final version, some typos were corrected. 21 pages, uses svmult.cl

First-Digit Law in Nonextensive Statistics

Nonextensive statistics, characterized by a nonextensive parameter $q$, is a promising and practically useful generalization of the Boltzmann statistics to describe power-law behaviors from physical and social observations. We here explore the unevenness of the first digit distribution of nonextensive statistics analytically and numerically. We find that the first-digit distribution follows Benford's law and fluctuates slightly in a periodical manner with respect to the logarithm of the temperature. The fluctuation decreases when $q$ increases, and the result converges to Benford's law exactly as $q$ approaches 2. The relevant regularities between nonextensive statistics and Benford's law are also presented and discussed.Comment: 11 pages, 3 figures, published in Phys. Rev.

Quasisymmetric graphs and Zygmund functions

A quasisymmetric graph is a curve whose projection onto a line is a quasisymmetric map. We show that this class of curves is related to solutions of the reduced Beltrami equation and to a generalization of the Zygmund class $\Lambda_*$. This relation makes it possible to use the tools of harmonic analysis to construct nontrivial examples of quasisymmetric graphs and of quasiconformal maps.Comment: 21 pages, no figure

Asexuality: Classification and characterization

This is a post-print version of the article. The official published version can be obtaineed at the link below.The term “asexual” has been defined in many different ways and asexuality has received very little research attention. In a small qualitative study (N = 4), individuals who self-identified as asexual were interviewed to help formulate hypotheses for a larger study. The second larger study was an online survey drawn from a convenience sample designed to better characterize asexuality and to test predictors of asexual identity. A convenience sample of 1,146 individuals (N = 41 self-identified asexual) completed online questionnaires assessing sexual history, sexual inhibition and excitation, sexual desire, and an open-response questionnaire concerning asexual identity. Asexuals reported significantly less desire for sex with a partner, lower sexual arousability, and lower sexual excitation but did not differ consistently from non-asexuals in their sexual inhibition scores or their desire to masturbate. Content analyses supported the idea that low sexual desire is the primary feature predicting asexual identity

The Surtsey volcano geothermal system: An analogue for seawater-oceanic crust interaction with implications for the elemental budget of the oceanic crust

Pre-print (óritrýnt handrit)Surtsey is a young volcanic island in the offshore extension of Iceland's southeast rift zone that grew from the seafloor during explosive and effusive eruptions in 1963–1967. In 1979, a cored borehole (SE-1) was drilled to 181 m depth and in 2017 three cored boreholes (SE-2a, SE-2b and SE-3) were drilled to successively greater depths. The basaltic deposits host a low-temperature (40–141 °C) seawater-dominated geothermal system. Surtsey provides an ideal environment to study water-rock interaction processes in a young seawater geothermal system. Elemental concentrations (SiO2, B, Na, Ca, Mg, F, dissolved inorganic carbon, SO4, Cl) and isotope contents (δD, δ18O) in borehole fluids indicate that associated geothermal waters in submarine deposits originated from seawater modified by reactions with the surrounding basalt. These processes produce authigenic minerals in the basaltic lapilli tuff and a corresponding depletion of certain elements in the residual waters. Coupling of measured and modelled concentrations investigates the effect of temperature and associated abundance of authigenic minerals on chemical fluxes from and to the igneous oceanic crust during low-temperature alteration. The annual chemical fluxes calculated at 50–150 °C range from −0.01 to +0.1×1012 mol yr−1 for SiO2, +0.2 to +129×1012 mol yr−1 for Ca, −129 to −0.8×1012 mol yr−1 for Mg and −21 to +0.4 × 1012 mol yr−1 for SO4 where negative values indicate chemical fluxes from the ocean into the oceanic crust and positive values indicate fluxes from the oceanic crust to the oceans. These flux calculations reveal that water-rock interaction at varying water-rock ratios and temperatures produces authigenic minerals that serve as important sinks of seawater-derived SiO2, Mg and SO4. In contrast, water rock interaction accompanied by dissolution of basaltic glass and primary crystal fragments provides a significant source of Ca. Such low-temperature alteration could effectively influence the elemental budget of the oceanic igneous crust and ocean waters. The modeling provides insights into water chemistries and chemical fluxes in low temperature MOR recharge zones. Surtsey also provides a valuable young analogue for assessing the chemical evolution of fluid discharge over the life cycles of seamounts in ridge flank systems.Funding for this project was provided by the University of Iceland Recruitment fund, the International Continental Scientific Drilling Program (ICDP) through a grant to the SUSTAIN project, the Icelandic Science Fund, ICF-RANNÍS, the Bergen Research Foundation and K.G. Jebsen Centre for Deep Sea Research at University of Bergen, Norway, the German Research Foundation (DFG), and DiSTAR, Federico II, University of Naples, Federico II, Italy. The University of Utah, USA and the two Icelandic power companies Reykjavík Energy and Landsvirkjun, contributed additional funds. The authors would like to thank P. Bergsten, A.M. di Stefano, C.F. Gorny, J. Gunnarsson-Robin, G.H. Guðfinsson, Þ. Högnadóttir, E.W. Marshall, R. Ólafssdóttir, D.B. Ragnarsson and Þ.M. Þorbjarnardóttir for their contribution and assistance during sampling, sample preparation, analyses and data evaluation. The authors would like to thank M. E. Böttcher for careful editorial handling. Two anonymous reviewers and J. Alt are thanked for their thoughtful and valuable reviews