Measuring the repertoire of age-related behavioral changes in Drosophila melanogaster

Aging affects almost all aspects of an organism -- its morphology, its physiology, its behavior. Isolating which biological mechanisms are regulating these changes, however, has proven difficult, potentially due to our inability to characterize the full repertoire of an animal's behavior across the lifespan. Using data from fruit flies (D. melanogaster) we measure the full repertoire of behaviors as a function of age. We observe a sexually dimorphic pattern of changes in the behavioral repertoire during aging. Although the stereotypy of the behaviors and the complexity of the repertoire overall remains relatively unchanged, we find evidence that the observed alterations in behavior can be explained by changing the fly's overall energy budget, suggesting potential connections between metabolism, aging, and behavior

Physics on the edge: contour dynamics, waves and solitons in the quantum Hall effect

We present a theoretical study of the excitations on the edge of a two-dimensional electron system in a perpendicular magnetic field in terms of a contour dynamics formalism. In particular, we focus on edge excitations in the quantum Hall effect. Beyond the usual linear approximation, a non-linear analysis of the shape deformations of an incompressible droplet yields soliton solutions which correspond to shapes that propagate without distortion. A perturbative analysis is used and the results are compared to analogous systems, like vortex patches in ideal hydrodynamics. Under a local induction approximation we find that the contour dynamics is described by a non-linear partial differential equation for the curvature: the modified Korteweg-de Vries equation. PACS number(s): 73.40.Hm, 02.40.Ma, 03.40.Gc, 11.10.LmComment: 15 pages, 12 embedded figures, submitted to Phys. Rev.

Nonlinear stabilitty for steady vortex pairs

In this article, we prove nonlinear orbital stability for steadily translating vortex pairs, a family of nonlinear waves that are exact solutions of the incompressible, two-dimensional Euler equations. We use an adaptation of Kelvin's variational principle, maximizing kinetic energy penalised by a multiple of momentum among mirror-symmetric isovortical rearrangements. This formulation has the advantage that the functional to be maximized and the constraint set are both invariant under the flow of the time-dependent Euler equations, and this observation is used strongly in the analysis. Previous work on existence yields a wide class of examples to which our result applies.Comment: 25 page

Solitons on the edge of a two-dimensional electron system

We present a study of the excitations of the edge of a two-dimensional electron droplet in a magnetic field in terms of a contour dynamics formalism. We find that, beyond the usual linear approximation, the non-linear analysis yields soliton solutions which correspond to uniformly rotating shapes. These modes are found from a perturbative treatment of a non-linear eigenvalue problem, and as solutions to a modified Korteweg-de Vries equation resulting from a local induction approximation to the nonlocal contour dynamics. We discuss applications to the edge modes in the quantum Hall effect.Comment: 4 pages, 2 eps figures (included); to appear in Phys. Rev. Letter

The construction of exact multipolar equilibria of the two-dimensional Euler equations

Published versio

Expanding Stereochemical and Skeletal Diversity Using Petasis Reactions and 1,3-Dipolar Cycloadditions

A short and modular synthetic pathway using intramolecular 1,3-dipolar cycloaddition reactions and yielding functionalized isoxazoles, isoxazolines, and isoxazolidines is described. The change in shape of previous compounds and those in this study is quantified and compared using principal moment-of-inertia shape analysis.Chemistry and Chemical Biolog

Randomized, phase II selection study of ramucirumab and paclitaxel versus FOLFIRI in refractory small bowel adenocarcinoma: SWOG S1922

Background: Small bowel adenocarcinoma is a rare malignancy with limited evidence to support the choice of systemic chemotherapy beyond the frontline setting. Though second-line therapy has historically been extrapolated from colorectal cancers, recent molecular data has demonstrated small bowel adenocarcinoma to be genomically unique when compared to either colon or gastric cancer. Retrospective analyses of irinotecan- and taxane-based therapies and one prospective phase II clinical trial of nab-paclitaxel have demonstrated clinical activity in this cancer. Ramucirumab/paclitaxel represents an active combination in the management of gastric cancer. SWOG 1922 evaluates the use of FOLFIRI or ramucirumab/paclitaxel in the second- and later-line setting for small bowel adenocarcinoma. Methods: This is randomized, phase II, selection design clinical trial of FOLFIRI (5-fluorouracil, leucovorin and irinotecan) every two weeks or ramucirumab D1,15 and paclitaxel D1,8,15 every 4 weeks with the primary endpoint of progression-free survival (PFS). Secondary endpoints include response rate, overall survival, and safety. Archived paraffin tumor tissue collection and serial blood collections are included for correlative analyses. Key eligibility criteria include having mismatch repair proficient/microsatellite stable small bowel adenocarcinoma (ampullary location excluded); metastatic or locally advanced unresectable disease; prior fluoropyrimidine and/or oxaliplatin therapy; no prior treatment with irinotecan, ramucirumab, or taxanes; no recent bleeding, blood clots, or bowel perforation/fistula; and Zubrod performance status of 0/1. Measurable disease is not required. The null hypothesis is median PFS of 2.5 months. If a median PFS of at least 3.5 months is observed in one or both arms, the goal is to choose the better regimen with respect to this endpoint. The design provides a 90% probability of selecting the more active arm, assuming a hazard ratio of 1.4, if both arms meet this threshold. This trial is open and, as of September 1, 2021, 21 of 94 planned patients have been enrolled