Chaotic transport in the homoclinic and heteroclinic tangle regions of quasiperiodically forced two-dimensional dynamical systems

The authors generalize notions of transport in phase space associated with the classical Poincare map reduction of a periodically forced two-dimensional system to apply to a sequence of nonautonomous maps derived from a quasiperiodically forced two-dimensional system. They obtain a global picture of the dynamics in homoclinic and heteroclinic tangles using a sequence of time-dependent two-dimensional lobe structures derived from the invariant global stable and unstable manifolds of one or more normally hyperbolic invariant sets in a Poincare section of an associated autonomous system phase space. The invariant manifold geometry is studied via a generalized Melnikov function. Transport in phase space is specified in terms of two-dimensional lobes mapping from one to another within the sequence of lobe structures, which provides the framework for studying several features of the dynamics associated with chaotic tangles

A global study of enhanced stretching and diffusion in chaotic tangles

A global, finite-time study is made of stretching and diffusion in a class of chaotic tangles associated with fluids described by periodically forced two-dimensional dynamical systems. Invariant lobe structures formed by intersecting global stable and unstable manifolds of persisting invariant hyperbolic sets provide the geometrical framework for studying stretching of interfaces and diffusion of passive scalars across these interfaces. In particular, the present study focuses on the material curve that initially lies on the unstable manifold segment of the boundary of the entraining turnstile lobe.A knowledge of the stretch profile of a corresponding curve that evolves according to the unperturbed flow, coupled with an appreciation of a symbolic dynamics that applies to the entire original material curve in the perturbed flow, provides the framework for understanding the mechanism for, and topology of, enhanced stretching in chaotic tangles. Secondary intersection points (SIP's) of the stable and unstable manifolds are particularly relevant to the topology, and the perturbed stretch profile is understood in terms of the unperturbed stretch profile approximately repeating itself on smaller and smaller scales. For sufficiently thin diffusion zones, diffusion of passive scalars across interfaces can be treated as a one-dimensional process, and diffusion rates across interfaces are directly related to the stretch history of the interface.An understanding of interface stretching thus directly translates to an understanding of diffusion across interfaces. However, a notable exception to the thin diffusion zone approximation occurs when an interface folds on top of itself so that neighboring diffusion zones overlap. An analysis which takes into account the overlap of nearest neighbor diffusion zones is presented, which is sufficient to capture new phenomena relevant to efficiency of mixing. The analysis adds to the concentration profile a saturation term that depends on the distance between neighboring segments of the interface. Efficiency of diffusion thus depends not only on efficiency of stretching along the interface, but on how this stretching is distributed relative to the distance between neighboring segments of the interface

Portfolio of musical compositions

INTRODUCTORY NOTE ON PERFORMANCE OF THE MUSIC HERE INCLUDED: This portfolio contains three works. The first, better now, is realised electronically; it has no score, and the six-channel version included herewith is the definitive performance source. A rendition in 5.1 surround is also included for referential convenience. This should not be used in public performance.The second and third works, Four Quartets and not even the rain, respectively, are scored for instrumental ensemble and voice and are intended to be performed as such. The recordings of these two pieces herewith included are synthetic, MIDI-based performances, which are included for the assistance of the score -reader only, because the timbral structure of the music is very important. These recordings should never be used for public performance

Substrate Properties and Fertilizer Rates on Yield Responses of Lettuce in a Vertical Growth System

The increased demand for food and the challenge for space for agriculture production in urban centers have made the vertical growth system an interesting trend. Agriculture is no longer only the horizontal, traditional, and soil grown method. Urban agriculture has created ways for inner city growers to be able to farm in a restricted space. Vertical farming is the practice of growing crops, especially leafy vegetables such as lettuce, in vertically stacked layers, as this results in significantly higher plant population per unit area. Two research trials were conducted in the fall of 2018 and the spring of 2019 to determine the effect of substrate properties and fertilizers on lettuce yield to optimize the urban production of lettuce. Three substrates (P3 + CF7 = Perlite 30%: Coco fiber 70%, PB7 + C3 = Pine Bark 70%: Compost 30%, and PB9 + C1 = Pine Bark 90%: Compost 10%) along with full and half rates of a fertilizer blend (VertiGro Organics fermented molasses, Ohrstrom’s Maxicrop liquid seaweed, and organic mineral blend) were evaluated on fresh and dried weight yield of lettuce. Substrate physical properties (air space, water holding capacity, total porosity, and bulk density) and substrate volumetric water content were also determined. ‘Nevada’ and ‘Optima’ lettuce varieties showed similar yield responses (fresh and dried weight) to substrate and fertilizer rates in both trials. In the fall 2018 trial, the highest fresh weight was observed in substrate PB7 + C3 with half fertilizer rate, with a mean plant weight of 41.13 g and 49.75 g for ‘Optima’ and ‘Nevada’, respectively. The least mean fresh weight was observed in half fertilizer rate of substrate P3 + CF7. For the spring 2019 trial, PB7 + C3 in half fertilizer strength gave the highest fresh weight for ‘Optima’ and ‘Nevada’ (45.64 g and 41.13 g, respectively). These values were statistically comparable to all other treatments except for substrate P3 + CF7 in full and half fertilizer which gave the least mean fresh weight. Volumetric water content in substrates P3 + CF7 recorded the highest average, while PB7 + C3 gave the least. Higher water holding capacity, total porosity, and lower airspace were observed in substrate P3 + CF7. Higher airspace was observed in PB9 + C1 but was comparable to PB7 + C3. PB7 + C3 gave the highest bulk density in both trials

Social origins, school type and higher education destinations

To what extent and why do social origins matter for access to higher education, including access to elite universities? What is the role of private and selective schooling? This paper uses the 1970 British Cohort Study (BCS70) to analyse the trajectories of a generation currently in early middle age. We find that the influence of social origins, especially parental education, remains when both a wide range of cognitive measures and school attainment are controlled. Attending a private school is powerfully predictive of gaining a university degree, and especially a degree from an elite institution, while grammar schooling does not appear to confer any advantage

Statistical relaxation under nonturbulent chaotic flows: Non-Gaussian high-stretch tails of finite-time Lyapunov exponent distributions

We observe that high-stretch tails of finite-time Lyapunov exponent distributions associated with interfaces evolving under a class of nonturbulent chaotic flows can range from essentially Gaussian tails to nearly exponential tails, and show that the non-Gaussian deviations can have a significant effect on interfacial evolution. This observation motivates new insight into stretch processes under chaotic flows

Apixaban overdose in children:case report and proposed management. A brief communication from the Pediatric and Neonatal Thrombosis and Hemostasis SSC of ISTH

Background: Direct oral anticoagulants are commonly prescribed for adults and increasingly also for children requiring anticoagulation therapy. While household medications should not be accessible to children, accidental, and intentional overdoses occur. Key Clinical Question: How should apixaban overdose in children be managed?. Clinical Approach: We present a case of an accidental overdose with the factor Xa antagonist apixaban in a young child and propose an approach to the management of cases of apixaban overdose in children. Conclusion: Given the increasing use of direct oral anticoagulants, it is important to have an approach to the management of overdose of these medications.</p

Apixaban overdose in children:case report and proposed management. A brief communication from the Pediatric and Neonatal Thrombosis and Hemostasis SSC of ISTH

Background: Direct oral anticoagulants are commonly prescribed for adults and increasingly also for children requiring anticoagulation therapy. While household medications should not be accessible to children, accidental, and intentional overdoses occur. Key Clinical Question: How should apixaban overdose in children be managed?. Clinical Approach: We present a case of an accidental overdose with the factor Xa antagonist apixaban in a young child and propose an approach to the management of cases of apixaban overdose in children. Conclusion: Given the increasing use of direct oral anticoagulants, it is important to have an approach to the management of overdose of these medications.</p