Singular measures in circle dynamics

Critical circle homeomorphisms have an invariant measure totally singular with respect to the Lebesgue measure. We prove that singularities of the invariant measure are of Holder type. The Hausdorff dimension of the invariant measure is less than 1 but greater than 0

Bilateral superficial ulnar artery with high origin from the axillary artery: its anatomy and clinical significance

The superficial ulnar artery (SUA) is a rare anatomical variant that usually arises either in the axilla or the arm and runs a superficial course in the forearm, enters the hand, and participates in the formation of superficial palmar arch. During the routine dissection of cadavers in the department of anatomy, whilst preparing the specimen for medical students, an unusual bilateral branch of the axillary artery was found in one of the cadavers: a rare variant of the artery known as SUA, which originates from the 2nd part of the axillary arteries of both sides. The SUA is a known anatomical variant, but the bilateral high origin from the 2nd part of the axillary artery is extremely unusual. Its occurrence is of great clinical importance to the surgical and radiological departments

Multifractal Scaling, Geometrical Diversity, and Hierarchical Structure in the Cool Interstellar Medium

Multifractal scaling (MFS) refers to structures that can be described as a collection of interwoven fractal subsets which exhibit power-law spatial scaling behavior with a range of scaling exponents (concentration, or singularity, strengths) and dimensions. The existence of MFS implies an underlying multiplicative (or hierarchical, or cascade) process. Panoramic column density images of several nearby star- forming cloud complexes, constructed from IRAS data and justified in an appendix, are shown to exhibit such multifractal scaling, which we interpret as indirect but quantitative evidence for nested hierarchical structure. The relation between the dimensions of the subsets and their concentration strengths (the "multifractal spectrum'') appears to satisfactorily order the observed regions in terms of the mixture of geometries present: strong point-like concentrations, line- like filaments or fronts, and space-filling diffuse structures. This multifractal spectrum is a global property of the regions studied, and does not rely on any operational definition of "clouds.'' The range of forms of the multifractal spectrum among the regions studied implies that the column density structures do not form a universality class, in contrast to indications for velocity and passive scalar fields in incompressible turbulence, providing another indication that the physics of highly compressible interstellar gas dynamics differs fundamentally from incompressible turbulence. (Abstract truncated)Comment: 27 pages, (LaTeX), 13 figures, 1 table, submitted to Astrophysical Journa

Clinical outcomes post transition to adult services in young adults with perinatally acquired HIV infection: mortality, retention in care, and viral suppression

OBJECTIVE: Adolescence is the only age group globally where HIV associated mortality is rising, with poorer outcomes at all stages of the care cascade compared to adults. We examined post-transition outcomes for young adults living with perinatal HIV (YAPaHIV). DESIGN: Retrospective cohort analysis. SETTING: A tertiary Youth Friendly Service (YFS) London, UK. PARTICIPANTS: 180 YAPaHIV registered between 01.01.06 and 31.12.17 contributed 921 person-years of follow up post-transition to adult services. INTERVENTION: YFS with multidisciplinary care and walk-in access. MAIN OUTCOME MEASURES: mortality, morbidity, retention in care, antiretroviral (ART) uptake and HIV-viral load (HIV-VL) suppression. Crude incidence rates (CIR) are reported per 1000 person-years. RESULTS: Of 180 youth registered; 4 (2.2%) died, 14 (7.8%) transferred care and 4 (2.2%) were lost to follow up. For the 158 retained in care the median age was 22.9 years (IQR 20.3-25.4), 56% were female, 85% Black African, with a median length of follow up in adult care of 5.5 years (IQR 2.9-7.3). 157 (99.4%) ever received an ART prescription, 127/157 (81%) with a latest HIV-VL < 200 copies RNA/ml, median CD4 count of 626 cells/ul (IQR 441-820). The all-cause mortality was 4.3/1000 person-years (95% CI 1.2 - 11.1), ten fold the aged-matched UK HIV-negative population (0.43/1000 person-years (95% CI 0.41 - 0.44). Post-transition, 17/180 (9.4%) developed a new AIDS diagnosis; CIR 18.5/1000 person-years (95% CI 10.8 - 29.6). CONCLUSION: Whilst this youth-friendly multi-disciplinary service achieved high engagement and coverage of suppressive ART, mortality remains markedly increased compared to the general UK population

Rheological Behavior of Aqueous Suspensions of Laponite: New Insights into the Ageing Phenomena

In this paper, ageing behavior of suspensions of laponite with varying salt concentration is investigated using rheological tools. It is observed that the ageing is accompanied by an increase in the complex viscosity. The succeeding creep experiments performed at various ages showed damped oscillations in the strain. The characteristic time-scale of the damped oscillations, retardation time, showed a prominent decrease with the age of the system. However, this dependence weakens with an increase in the salt concentration, which is known to change microstructure of the system from glass-like to gel-like. We postulate that a decrease in the retardation time can be represented as a decrease in the viscosity (friction) of the dissipative environment surrounding the arrested entities that opposes elastic deformation of the system. We believe that ageing in colloidal glass leads to a greater ordering that enhances relative spacing between the constituents thereby reducing the frictional resistance. However, since a gel state is inherently different in structure (fractal network) than that of a glass (disordered), ageing in the same does not induce ordering. Consequently, we observe inverse dependence of retardation time on age becoming weaker with an increase in the salt concentration. We analyze these results from a perspective of ageing dynamics of both glass state and gel state of laponite suspensions.Comment: 27 Pages, 12 figure

Multifractal burst in the spatio-temporal dynamics of jerky flow

The collective behavior of dislocations in jerky flow is studied in Al-Mg polycrystalline samples subjected to constant strain rate tests. Complementary dynamical, statistical and multifractal analyses are carried out on the stress-time series recorded during jerky flow to characterize the distinct spatio-temporal dynamical regimes. It is shown that the hopping type B and the propagating type A bands correspond to chaotic and self-organized critical states respectively. The crossover between these types of bands is identified by a large spread in the multifractal spectrum. These results are interpreted on the basis of competing scales and mechanisms.Comment: 4 pages, 6 figures To be published in Phys. Rev. Lett. (2001

Flow induced by a sphere settling in an aging yield-stress fluid

We have studied the flow induced by a macroscopic spherical particle settling in a Laponite suspension that exhibits a yield-stress, thixotropy and shear-thinning. We show that the fluid thixotropy (or aging) induces an increase with time of both the apparent yield stress and shear-thinning properties but also a breaking of the flow fore-aft symmetry predicted in Hershel-Bulkley fluids (yield-stress, shear-thinning fluids with no thixotropy). We have also varied the stress exerted by the particles on the fluid by using particles of different densities. Although the stresses exerted by the particles are of the same order of magnitude, the velocity field presents utterly different features: whereas the flow around the lighter particle shows a confinement similar to the one observed in shear-thinning fluids, the wake of the heavier particle is characterized by an upward motion of the fluid ("negative wake"), whatever the fluid's age. We compare the features of this negative wake to the one observed in viscoelastic shear-thinning fluids (polymeric or micelle solutions). Although the flows around the two particles strongly differ, their settling behaviors display no apparent difference which constitutes an intriguing result and evidences the complexity of the dependence of the drag factor on flow field