Beating dark-dark solitons in Bose-Einstein condensates

Motivated by recent experimental results, we study beating dark-dark solitons as a prototypical coherent structure that emerges in two-component Bose-Einstein condensates. We showcase their connection to dark- bright solitons via SO(2) rotation, and infer from it both their intrinsic beating frequency and their frequency of oscillation inside a parabolic trap. We identify them as exact periodic orbits in the Manakov limit of equal inter- and intra-species nonlinearity strengths with and without the trap and showcase the persistence of such states upon weak deviations from this limit. We also consider large deviations from the Manakov limit illustrating that this breathing state may be broken apart into dark-antidark soliton states. Finally, we consider the dynamics and interactions of two beating dark-dark solitons in the absence and in the presence of the trap, inferring their typically repulsive interaction.Comment: 13 pages, 14 figure

30 Years of Cystocele/Rectocele Repair in the United States

Objective: A growing body of evidence suggests an increased role for apical support in the treatment of pelvic organ prolapse regardless of phenotype. The objective of this study was to determine whether changes in cystocele/rectocele diagnosis and surgical management for the last 30 years reflect this changing paradigm. Methods: Data from the National Hospital Discharge Survey were mined from 1979 to 2009 for diagnosis and procedure codes. Records were categorized according to predefined combinations of diagnosis and procedure codes and weighted according to the National Hospital Discharge Survey data set. Pearson [chi]2 test was used to evaluate the changes in population proportions during the study interval. Results: The proportion of isolated cystocele/rectocele diagnoses decreased from 1979 to 2009 (56.5%, n = 88,548, to 34.8%, n = 31,577). The proportion of isolated apical defect diagnoses increased from 1979 to 2009 (38.4%, n = 60,223, to 60.8%, n = 55,153). There was a decrease in the frequency of isolated cystocele/rectocele repair procedures performed from 1979 to 2009 (96.3%, n = 150,980, to 67.7%, n = 61,444), whereas there was an increase in isolated apical defect repair procedures (2.5%, n = 3929, to 22.5%, n = 20,450). The proportion of cystocele/rectocele plus apical defect procedures also increased (1.2%, n = 1879, to 9.7%, n = 8806). Furthermore, 87.0% of all studied diagnostic groups were managed by cystocele/rectocele repair alone. Conclusions: Surgeons have responded to the increased contribution of apical support defects to cystocele/rectocele by modifying their diagnostic coding practices. Unfortunately, their surgical choices remain largely rooted in an older paradigm

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Characterizing Sympathetic Neurovascular Transduction in Humans

Despite its critical role for cardiovascular homeostasis in humans, only a few studies have directly probed the transduction of sympathetic nerve activity to regional vascular responses – sympathetic neurovascular transduction. Those that have variably relied on either vascular resistance or vascular conductance to quantify the responses. However, it remains unclear which approach would better reflect the physiology. We assessed the utility of both of these as well as an alternative approach in 21 healthy men. We recorded arterial pressure (Finapres), peroneal sympathetic nerve activity (microneurography), and popliteal blood flow (Doppler) during isometric handgrip exercise to fatigue. We quantified and compared transduction via the relation of sympathetic activity to resistance and to conductance and via an adaptation of Poiseuille’s relation including pressure, sympathetic activity, and flow. The average relationship between sympathetic activity and resistance (or conductance) was good when assessed over 30-second averages (mean R$^2$=0.49±0.07) but lesser when incorporating beat-by-beat time lags (R$^2$=0.37±0.06). However, in a third of the subjects, these relations provided relatively weak estimates (R$^2$0.50 in 20 of 21 individuals), and provided reproducible estimates of transduction. The gain derived from the relation of resistance (but not conductance) was inversely related to transduction (R$^2$=0.37, p<0.05), but with a proportional bias. Thus, vascular resistance and conductance may not always be reliable surrogates for regional sympathetic neurovascular transduction, and assessment from a Poiseuille relation between pressure, sympathetic nerve activity, and flow may provide a better foundation to further explore differences in transduction in humans