8 research outputs found
Stable ring vortex solitons in Bessel optical lattices
Stable ring vortex solitons, featuring a bright-shape, appear to be very rare
in nature. However, here we show that they exist and can be made dynamically
stable in defocusing cubic nonlinear media with an imprinted Bessel optical
lattice. We find the families of vortex lattice solitons and reveal their
salient properties, including the conditions required for their stability. We
show that the higher the soliton topological charge, the deeper the lattice
modulation necessary for stabilization.Comment: 14 pages, 4 figures, submitted to Physical Review Letter
Rotary solitons in Bessel photonic lattices
We introduce solitons supported by Bessel photonic lattices in cubic
nonlinear media. We show that the cylindrical geometry of the lattice, with
several concentric rings, affords unique soliton properties and dynamics. In
particular, besides the lowest-order solitons trapped in the center of the
lattice, we find soliton families trapped at different lattice rings. Such
solitons can be set into controlled rotation inside each ring, thus featuring
novel types of in-ring and inter-ring soliton interactions.Comment: 12 pages, 4 figures. to appear in Physical Review Letter
Macrosomia and large for gestational age in Asia:One size does not fit all
Macrosomia, usually defined as infant birth weight of >= 4000 g, does not consider gestational age, sex, or country/region-specific differences in mean birth weight and maternal body weight. This issue is particularly relevant for Asia, where 60% of the world's population lives, due to variations in maternal size and birth weights across populations. Large for gestational age (LGA), defined as birth weight > 90th centile, is a more sensitive measure as it considers gestational age and sex, though it is dependent on the choice of growth charts. We aimed to review reporting of macrosomia and LGA in Asia. We reviewed the literature on prevalence and risk of macrosomia and LGA in Asia over the last 29 years. Prevalence of macrosomia ranged from 0.5% (India) to 13.9% (China) while prevalence of LGA ranged from 4.3% (Korea) to 22.1% (China), indicating substantial variation in prevalence within and between Asian countries. High pre-pregnancy body mass index, excessive gestational weight gain, and impaired glucose tolerance conferred risk of macrosomia/LGA. Incidence of macrosomia and LGA varies substantially within and between Asian countries, as do the growth charts and definitions. The latter makes it impossible to make comparisons but suggests differences in intrauterine growth between populations. Reporting LGA, using standardized country/regional growth charts, would better capture the incidence of high birth weight and allow for comparison and identification of contributing factors. Better understanding of local drivers of excessive intrauterine growth could enable development of improved strategies for prevention and management of LGA
Ultrafast laser micro-nano structuring of transparent materials with high aspect ratio
Ultrafast lasers are ideal tools to process transparent materials because
they spatially confine the deposition of laser energy within the material's
bulk via nonlinear photoionization processes. Nonlinear propagation and
filamentation were initially regarded as deleterious effects. But in the last
decade, they turned out to be benefits to control energy deposition over long
distances. These effects create very high aspect ratio structures which have
found a number of important applications, particularly for glass separation
with non-ablative techniques. This chapter reviews the developments of
in-volume ultrafast laser processing of transparent materials. We discuss the
basic physics of the processes, characterization means, filamentation of
Gaussian and Bessel beams and provide an overview of present applications