bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cubic critical portraits and polynomials with wandering gaps
Authors: BLOKH ALEXANDER , CURRY CLINTON , OVERSTEEGEN LEX 
Published: August 2012

AbstractThurston introduced $\sigma _d$-invariant laminations (where $\sigma _d(z)$ coincides with $z^d:\mathbb S ^1\to \mathbb S ^1$, $d\ge 2$) and defined wandering $k$-gons as sets ${\mathbf {T}}\subset \mathbb S ^1$ such that $\sigma _d^n({\mathbf {T}})$ consists of $k\ge 3$ distinct points for all $n\ge 0$ and the convex hulls of all the sets $\sigma _d^n({\mathbf {T}})$ in the plane are pairwise disjoint. He proved that $\sigma _2$ has no wandering $k$-gons. Call a lamination with wandering $k$-gons a WT-lamination. In a recent paper, it was shown that uncountably many cubic WT-laminations, with pairwise non-conjugate induced maps on the corresponding quotient spaces $J$, are realizable as cubic polynomials on their (locally connected) Julia sets. Here we use a new approach to construct cubic WT-laminations with the above properties so that any wandering branch point of $J$ has a dense orbit in each subarc of $J$ (we call such orbits condense), and show that critical portraits corresponding to such laminations are dense in the space ${\mathcal A}_3$of all cubic critical portraits.
Stokes flow near the contact line of an evaporating drop
Authors: Gelderblom Hanneke , Bloemen Oscar , Snoeijer Jacco H. 
Published: August 2012

AbstractThe evaporation of sessile drops in quiescent air is usually governed by vapour diffusion. For contact angles below $9{0}^{\ensuremath{\circ} } $, the evaporative flux from the droplet tends to diverge in the vicinity of the contact line. Therefore, the description of the flow inside an evaporating drop has remained a challenge. Here, we focus on the asymptotic behaviour near the pinned contact line, by analytically solving the Stokes equations in a wedge geometry of arbitrary contact angle. The flow field is described by similarity solutions, with exponents that match the singular boundary condition due to evaporation. We demonstrate that there are three contributions to the flow in a wedge: the evaporative flux, the downward motion of the liquid–air interface and the eigenmode solution which fulfils the homogeneous boundary conditions. Below a critical contact angle of $133. {4}^{\ensuremath{\circ} } $, the evaporative flux solution will dominate, while above this angle the eigenmode solution dominates. We demonstrate that for small contact angles, the velocity field is very accurately described by the lubrication approximation. For larger contact angles, the flow separates into regions where the flow is reversing towards the drop centre.
Asymptotic calculation of the dynamics of self-sustained detonations in condensed phase explosives
Authors: Saenz J. A. , Taylor B. D. , Stewart D. S. 
Published: August 2012

AbstractWe use the weak-curvature, slow-time asymptotics of detonation shock dynamics (DSD) to calculate an intrinsic relation between the normal acceleration, the normal velocity and the curvature of a lead detonation shock for self-sustained detonation waves in condensed phase explosives. The formulation uses the compressible Euler equations for an explosive that is described by a general equation of state with multiple reaction progress variables. The results extend an earlier asymptotic theory for a polytropic equation of state and a single-step reaction rate model discussed by Kasimov (Theory of instability and nonlinear evolution of self-sustained detonation waves. PhD thesis, University of Illinois Urbana-Champaign, Urbana, Illinois) and by Kasimov & Stewart (Phys. Fluids, vol. 16, 2004, pp. 3566–3578). The asymptotic relation is used to study the dynamics of ignition events in solid explosive PBX-9501 and in porous PETN powders. In the case of porous or powdered explosives, two composition variables are used to represent the extent of exothermic chemical reaction and endothermic compaction. Predictions of the asymptotic formulation are compared against those of alternative DSD calculations and against shock-fitted direct numerical simulations of the reactive Euler equations.
The surface signature of internal waves
Authors: Craig W. , Guyenne P. , Sulem C. 
Published: August 2012

AbstractOceans that are stratified by density into distinct layers support internal waves. An internal soliton gives rise to characteristic features on the surface, a signature of its presence, in the form of a ‘rip’ region, as reported in Osborne & Burch (Science, vol. 208, 1980, pp. 451–460), which results in a change in reflectance as seen in NASA photographs from the space shuttle. In the present paper, we give a new analysis of this signature of an internal soliton, and the ‘mill pond’ effect of an almost completely calm sea after its passage. Our analysis models the resonant interaction of nonlinear internal waves with the surface modes, where the surface signature is generated by a process analogous to radiative absorption. These theoretical results are illustrated with numerical simulations that take oceanic parameters into account.
On the universality of turbulent axisymmetric wakes
Authors: Redford John A. , Castro Ian P. , Coleman Gary N. 
Published: September 2012

AbstractDirect numerical simulations (DNS) of two time-dependent, axially homogeneous, axisymmetric turbulent wakes having very different initial conditions are presented in order to assess whether they reach a universal self-similar state as classically hypothesized by Townsend. It is shown that an extensive early-time period exists during which the two wakes are individually self-similar with wake widths growing like$\delta \propto {t}^{1/ 3} $, as predicted by classical dimensional analysis, but have very different growth rates and are thus not universal. Subsequently, however, the turbulence adjusts to yield, eventually, wakes that are structurally identical and have the same growth rate (also with$\delta \propto {t}^{1/ 3} $) so provide clear evidence of a universal, self-similar state. The former non-universal but self-similar state extends, in terms of a spatially equivalent flow behind a spherical body of diameter$d$, to a distance of$O(3000d)$whereas the final universal state does not appear before$O(5000d)$(and exists despite relatively low values of the Reynolds number and no evidence of a spectral${\kappa }^{\ensuremath{-} 5/ 3} $inertial subrange). Universal wake evolution is therefore likely to be rare in practice. Despite its low Reynolds number, the flow does not exhibit the sometime-suggested alternative self-similar behaviour with$\delta \propto {t}^{1/ 2} $(as for the genuinely laminar case) at large times (or, equivalently, distances), since the eddy viscosity remains large compared to the molecular viscosity and its temporal variations are not negligible.
Educing the source mechanism associated with downstream radiation in subsonic jets
Authors: Kerhervé F. , Jordan P. , Cavalieri A. V. G. , Delville J. , Bogey C. , Juvé D. 
Published: August 2012

AbstractThis work belongs to the ongoing debate surrounding the mechanism responsible for low-angle sound emission from subsonic jets. The flow, simulated by large eddy simulation (Bogey & Bailly,Comput. Fluids, vol. 35 (10), 2006a, pp. 1344–1358), is a Mach 0.9 jet with Reynolds number, based on the exit diameter, of$4\ensuremath{\times} 1{0}^{5} $. A methodology is implemented to educe, explore and model the flow motions associated with low-angle sound radiation. The eduction procedure, which is based on frequency–wavenumber filtering of the sound field and subsequent conditional analysis of the turbulent jet, provides access to space- and time-dependent (hydrodynamic) pressure and velocity fields. Analysis of these shows the low-angle sound emission to be underpinned by dynamics comprising space and time modulation of axially coherent wavepackets: temporally localized energization of wavepackets is observed to be correlated with the generation of high-amplitude acoustic bursts. Quantitative validation is provided by means of a simplified line-sourceAnsatz(Cavalieriet al. J. Sound Vib., vol. 330, 2011b, pp. 4474–4492). The dynamic nature of the educed field is then assessed using linear stability theory (LST). The educed pressure and velocity fields are found to compare well with LST: the radial structures of these match the corresponding LST eigenfunctions; the axial evolutions of their fluctuation energy are consistent with the LST amplification rates; and the relative amplitudes of the pressure and velocity fluctuations, which are educed independently of one another, are consistent with LST.
Giambattista Della Porta and the Roman Inquisition: censorship and the definition of Nature's limits in sixteenth-century Italy
Authors: TARRANT NEIL 
Published: August 2012

AbstractIt has long been noted that towards the end of the sixteenth century the Catholic Church began to use its instruments of censorship – the Inquisition and the Index of Forbidden Books – to prosecute magic with increased vigour. These developments are often deemed to have had important consequences for the development of modern science in Italy, for they delimited areas of legitimate investigation of the natural world. Previous accounts of the censorship of magic have tended to suggest that the Church as an institution was opposed to, and sought to eradicate, the practice of magic. I do not seek to contest the fact that ecclesiastical censors prosecuted various magical and divinatory practices with greater enthusiasm at this time, but I suggest that in order to understand this development more fully it is necessary to offer a more complex picture of the Church. In this article I use the case of the Neapolitan magus Giambattista Della Porta to argue that during the course of the century the acceptable boundaries of magical speculation became increasingly clearly defined. Consequently, many practices and techniques that had previously been of contested orthodoxy were categorically defined as heterodox and therefore liable to prosecution and censorship. I argue, however, that this development was not driven by the Church asserting a ‘traditional’ hostility towards magic, but was instead the result of one particular faction within the Church embedding their conception of orthodox philosophical investigation of the natural world within the machinery of censorship.
Recycling in early modern science
Authors: WERRETT SIMON 
Published: August 2012

AbstractThis essay follows recent work in environmental history to explore the history of recycling in physical sciences in Britain and North America since the seventeenth century. The term ‘recycling’ is here used broadly to refer to a variety of practices that extended the life of material resources for doing science in the early modern period. These included practices associated with maintenance, repair, exchange and the adaptation or reuse of material culture. The essay argues that such practices were common in early modern science, and informed experimental spaces and techniques and the ideas that they generated. The essay considers some of the varied motivations that led to such practices, and concludes by examining the endurance of recycling in science since the end of the eighteenth century, particularly in recent efforts to create sustainable scientific research practices.
Fossil dealers, the practices of comparative anatomy and British diplomacy in Latin America, 1820–1840
Authors: PODGORNY IRINA 
Published: August 2012

AbstractThis paper traces the trade routes of South American fossil mammal bones in the 1830s, thus elaborating both local and intercontinental networks that ascribed new meanings to objects with little intrinsic value. It analyses the role of British consuls, natural-history dealers, administrative instructions and naturalists, who took the bones from the garbage pits of ranches outside Buenos Aires and delivered them into the hands of anatomists. For several years, the European debates on the anatomy ofMegatheriumwere shaped by the arrival in London of a small living mammal and the ideas and evidence received from Montevideo on the existence of huge fossil bony armours. These debates culminated late in 1838 in the creation of the extinct genusGlyptodonby Richard Owen as a result of the exchange of letters, objects and depictions, and a series of contingent events. Based on primary sources and South American scholarship, this paper aims to contribute to the current debates among historians of science about the mobility of knowledge, as well as presenting the condition that made Charles Darwin's work possible.
Secularism and the cultures of nineteenth-century scientific naturalism
Authors: RECTENWALD MICHAEL 
Published: August 2012

AbstractThis essay examines Secularism as developed by George Jacob Holyoake in 1851–1852. While historians have noted the importance of evolutionary thought for freethinking radicals from the 1840s, and others have traced the popularization of agnosticism and Darwinian evolution by later Victorian freethinkers, insufficient attention has been paid to mid-century Secularism as constitutive of the cultural and intellectual environment necessary for the promotion and relative success of scientific naturalism. I argue that Secularism was a significant source for the emerging new creed of scientific naturalism in the mid-nineteenth century. Not only did early Secularism help clear the way by fighting battles with the state and religious interlocutors, but it also served as a source for what Huxley, almost twenty years later, termed ‘agnosticism’. Holyoake modified freethought in the early 1850s, as he forged connections with middle-class literary radicals and budding scientific naturalists, some of whom met in a ‘Confidential Combination’ of freethinkers. Secularism became the new creed for this coterie. Later, Secularism promoted and received reciprocal support from the most prominent group of scientific naturalists, as Holyoake used Bradlaugh's atheism and neo-Malthusianism as a foil, and maintained relations with Huxley, Spencer and Tyndall through the end of the century. In Holyoake's Secularism we find the beginnings of the mutation of radical infidelity into the respectability necessary for the acceptance of scientific naturalism, and also the distancing of later forms of infidelity incompatible with it. Holyoake's Secularism represents an important early stage of scientific naturalism.
Antioxidant status and its association with elevated depressive symptoms among US adults: National Health and Nutrition Examination Surveys 2005–6
Authors: Beydoun May A. , Beydoun Hind A. , Boueiz Adel , Shroff Monal R. , Zonderman Alan B. 
Published: August 2012

We examined the relationship of elevated depressive symptoms with antioxidant status. Cross-sectional data from the National Health and Nutrition Examination Surveys 2005–6 on US adults aged 20–85 years were analysed. Depressive symptoms were measured using the Patient Health Questionnaire with a score cut-off point of 10 to define ‘elevated depressive symptoms’. Serum antioxidant status was measured by serum levels of carotenoids, retinol (free and retinyl esters), vitamin C and vitamin E. The main analyses consisted of multiple logistic and zero-inflated Poisson regression models, taking into account sampling design complexity. The final sample consisted of 1798 US adults with complete data. A higher total serum carotenoid level was associated with a lower likelihood of elevated depressive symptoms with a reduction in the odds by 37 % overall with eachsdincrease in exposure, and by 34 % among women (P< 0·05). A dose–response relationship was observed when total serum carotenoids were expressed as quartiles (Q4 (1·62–10·1 μmol/l)v.Q1(0·06–0·86 μmol/l): OR 0·41; 95 % CI 0·23, 0·76,P< 0·001;Pfor trend = 0·035), though no significant associations were found with the other antioxidant levels. Among carotenoids, β-carotene (men and women combined) and lutein+zeaxanthins (women only, after control for dietary lutein+zeaxanthin intake and supplement use) had an independent inverse association with elevated depressive symptoms among US adults. None of the other serum antioxidants had a significant association with depressive symptoms, independently of total carotenoids and other covariates. In conclusion, total carotenoids (mainly β-carotene and lutein+zeaxanthins) in serum were associated with reduced levels of depressive symptoms among community-dwelling US adults.
Associations of plasma phospholipid fatty acids with plasma homocysteine in Chinese vegetarians
Authors: Huang Tao , Yu Xiaomei , Shou Tianxing , Wahlqvist Mark L. , Li Duo 
Published: August 2012

The association of plasma phospholipid (PL) fatty acid composition with plasma homocysteine (Hcy) in Chinese vegetarians is not understood. The main aim of the present study was to investigate the plasma PL fatty acid status, and its association with plasma Hcy in Chinese vegetarians and omnivores. A total of 103 male vegetarians and 128 male omnivores were recruited in Linyin Temple, Hangzhou. Plasma Hcy and PL fatty acid concentrations were determined by standard methods. Compared with omnivores, plasma PLn-3 PUFA (P< 0·001), 22 : 6n-3 (P< 0·001), 22 : 5n-6 (P= 0·021), 22 : 2n-6 (P< 0·001) and SFA (P= 0·017) were significantly lower, while plasma PLn-6 PUFA (P= 0·007) and total PUFA (P< 0·001) were significantly higher in vegetarians. The prevalence of hyperhomocysteinaemia (HHcy) in vegetarians (26·47 %) was significantly higher than that in omnivores (13·28 %). In vegetarians, plasma PL 22 : 6n-3 (r− 0·257,P= 0·046) was significantly negatively associated with plasma Hcy. In omnivores, plasma PL 18 : 1n-7 (r0·237,P= 0·030) was significantly positively associated with plasma Hcy. Plasma PL 22 : 6n-3 (r− 0·217,P= 0·048) was negatively associated with plasma Hcy in omnivores. Plasma PL SFA were positively associated with the prevalence of HHcy. It would seem appropriate for vegetarians to increase their dietaryn-3 PUFA and decrease dietary SFA, and thus reduce the risk of HHcy.
Agreement of bioelectrical impedance with dual-energy X-ray absorptiometry and MRI to estimate changes in body fat, skeletal muscle and visceral fat during a 12-month weight loss intervention
Authors: Pietiläinen Kirsi H. , Kaye Sanna , Karmi Anna , Suojanen Laura , Rissanen Aila , Virtanen Kirsi A. 
Published: August 2012

The aim of the present study was to analyse the agreement of bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA) and MRI in estimating body fat, skeletal muscle and visceral fat during a 12-month weight loss intervention. A total of nineteen obese adults (twelve females, seven males) aged 20·2–48·6 years, mean BMI 34·6 (se 0·6) kg/m2, participated in the study. Body fat, skeletal muscle and visceral fat index were measured by BIA (Omron BF-500; Omron Medizintechnik) and compared with DXA (body fat and skeletal muscle) at baseline, 5 and 12 months, and with MRI (visceral fat) at baseline and 5 months. The subjects lost 8·9 (se 1·8) kg (9·0 (se 1·7) %) of body weight during the 12-month intervention. BIA, as compared to DXA, accurately assessed loss of fat (7·0 (se 1·5) v. 7·0 (se 1·4) kg, P= 0·94) and muscle (1·0 (se 0·2) v. 1·4 (se 0·3) kg, P= 0·18). While body fat was similar by the two methods, skeletal muscle was underestimated by 1–2 kg using BIA at each time point. Compared to MRI, BIA overestimated visceral fat, especially in males. BIA and DXA showed high correlations for kg fat, both cross-sectionally and longitudinally (r 0·91–0·99). BIA, compared with DXA and MRI, detected kg muscle and visceral fat more accurately cross-sectionally (r 0·77–0·87 and r 0·40–0·78, respectively) than their changes longitudinally (r 0·24–0·61 and r 0·46, respectively). BIA is at its best when assessing the amount or changes in fat mass. It is a useful method for measuring skeletal muscle, but limited in its ability to measure visceral fat.
Immunoprotective effects of oral intake of heat-killed Lactobacillus pentosus strain b240 in elderly adults: a randomised, double-blind, placebo-controlled trial
Authors: Shinkai Shoji , Toba Masamichi , Saito Takao , Sato Ikutaro , Tsubouchi Mina , Taira Kiyoto , Kakumoto Keiji , Inamatsu Takashi , Yoshida Hiroto , Fujiwara Yoshinori , Fukaya Taro , Matsumoto Tetsuya , Tateda Kazuhiro , Yamaguchi Keizo , Kohda Noriyuki , Kohno Shigeru 
Published: September 2012

Oral intake of Lactobacillus pentosus strain b240 (b240) has been shown to enhance the secretion of salivary secretory IgA in elderly adults. However, its clinical benefits remain to be determined. We tested the hypothesis that b240 exerts a protective effect against the common cold in elderly adults. The design of the present study was a randomised, double-blind, placebo-controlled trial (RCT) with parallel three-group comparison. For this purpose, 300 eligible elderly adults were randomly allocated to one of three groups, namely a placebo, low-dose or high-dose b240 group. Participants in the low-dose and high-dose b240 groups were given tablets containing 2 × 109 or 2 × 1010 cells, respectively, of heat-killed b240, while those in the placebo group were given tablets without b240. Each group consumed their respective tablets once daily for 20 weeks. The common cold was assessed on the basis of a diary. Change in quality of life was evaluated using the SF-36®. Of the total participants, 280 completed the 20-week RCT. The accumulated incidence rate of the common cold was 47·3, 34·8 and 29·0 % for the placebo, low-dose b240 and high-dose b240 groups, respectively (P for trend = 0·012). Lower incidence rates were consistently observed throughout the experimental period in the b240 groups (log-rank test, P= 0·034). General health perception, as determined by the SF-36®, dose-dependently increased in the b240 groups (P for trend = 0·016). In conclusion, oral intake of b240 significantly reduced the incidence rate of the common cold in elderly adults, indicating that b240 might be useful in improving resistance against infection through mucosal immunity.
Is there a bidirectional relationship between depressive symptoms and cognitive ability in older people? A prospective study using the English Longitudinal Study of Ageing
Authors: Gale C. R. , Allerhand M. , Deary I. J. 
Published: September 2012

BackgroundCross-sectional surveys of older people commonly find associations between higher levels of depressive symptoms and poorer cognitive performance, but the direction of effect is unclear. We examined whether there was a bidirectional relationship between depressive symptoms and general cognitive ability in non-demented older people, and explored the role of physical health, smoking, exercise, social class and education as potential confounders of this association and as possible determinants of the rate of change of cognitive decline and depressive symptoms.MethodThe English Longitudinal Study of Ageing consists of people aged 50 years and over. Cognitive function and self-reported depressive symptoms were measured in 2002–2003, 2004–2005, 2006–2007 and 2008–2009. We fitted linear piecewise models with fixed knot positions to allow different slopes for different age groups. Analyses are based on 8611 people.ResultsMean cognitive function declined with age; there was no trend in the trajectory of depressive symptoms. Better cognitive function was associated with less depression up to the age of 80 years. Greater depression was associated with a slightly faster rate of cognitive decline but only in people aged 60–80 years. There were no consistent associations across age groups between sex, smoking, education, social class, exercise or number of chronic physical illnesses and the rate of change of cognitive decline or depressive symptoms.ConclusionsIn this longitudinal study of older people, there was no consistent evidence that being more depressed led to an acceleration in cognitive decline and no support for the hypothesis that there might be reciprocal dynamic influences between cognitive ability and depressive symptoms.