Maximal Hamiltonian tori for polygon spaces

We study the poset of Hamiltonian tori for polygon spaces. We determine some maximal elements and give examples where maximal Hamiltonian tori are not all of the same dimension.Comment: 15 pages, Latex, 1 figur

Reversibility of cell surface label rearrangement

Cell surface labeling can cause rearrangements of randomly distributed membrane components. Removal of the label bound to the cell surface allows the membrane components to return to their original random distribution, demonstrating that label is necessary to maintain as well as to induce rearrangements. With scanning electron microscopy, the rearrangement of concanavalin A (con A) and ricin binding sites on LA-9 cells has been followed by means of hemocyanin, a visual label. The removal of con A from its binding sites at the cell surface with alpha- methyl mannoside, and the return of these sites to their original distribution are also followed in this manner. There are labeling differences with con A and ricin. Under some conditions, however, the same rearrangements are seen with both lectins. The disappearance of labeled sites from areas of ruffling activity is a major feature of the rearrangements seen. Both this ruffling activity and the rearrangement of label are sensitive to cytochalasin B, and ruffling activity, perhaps along with other cytochalasin-sensitive structure, may play a role in the rearrangements of labeled sites

The Dunhuang chinese sky: a comprehensive study of the oldest known star atlas

This paper presents an analysis of the star atlas included in the medieval Chinese manuscript (Or.8210/S.3326), discovered in 1907 by the archaeologist Aurel Stein at the Silk Road town of Dunhuang and now held in the British Library. Although partially studied by a few Chinese scholars, it has never been fully displayed and discussed in the Western world. This set of sky maps (12 hour angle maps in quasi-cylindrical projection and a circumpolar map in azimuthal projection), displaying the full sky visible from the Northern hemisphere, is up to now the oldest complete preserved star atlas from any civilisation. It is also the first known pictorial representation of the quasi-totality of the Chinese constellations. This paper describes the history of the physical object - a roll of thin paper drawn with ink. We analyse the stellar content of each map (1339 stars, 257 asterisms) and the texts associated with the maps. We establish the precision with which the maps are drawn (1.5 to 4 degrees for the brightest stars) and examine the type of projections used. We conclude that precise mathematical methods were used to produce the atlas. We also discuss the dating of the manuscript and its possible author and confirm the dates 649-684 (early Tang dynasty) as most probable based on available evidence. This is at variance with a prior estimate around +940. Finally we present a brief comparison with later sky maps, both in China and in Europe.Comment: 19 pages, 5 Tables, 8 Figure

Investigation of water displacement following large CO2 sequestration operations

The scale of CO2 injection into the subsurface required to address CO2 atmospheric concentrations is unprecedented. Multiple injection sites injecting into multiple formations will create a large excess pressure zone extending far beyond the limited volume where CO2 is present. In a closed system, additional mass is accommodated by the compressibility of system components, an increase in fluid pressure, and possibly an uplift of the land surface. In an open system, as assumed in this analysis, another coping mechanism involves fluid flux out of the boundaries of the system, in which case the fresh-water-bearing outcrop areas, corresponding to the up-dip sections of the down-dip formations into which CO2 is injected, could be impacted. A preliminary study using a MODFLOW groundwater model extending far down-dip shows that injecting a large amount of fluid does have an impact some distance away from the injection area but most likely only in localized areas. A major assumption of this preliminary work was that multiphase processes do not matter some distance away from the injection zones. In a second step, presented in this paper, to demonstrate that a simplified model can yield results as useful as those of a more sophisticated multiphase-flow compositional model, we model the same system using CMG-GEM software. Because the chosen software lacks the ability to deal easily with unconfined water flow, we compare fluxes through time, as given by MODFLOW and CMG-GEM models at the confined/unconfined interface.Bureau of Economic Geolog

Use of Interdisciplinary Education to Foster Familiarization among Health Professionals

This paper describes a pilot interdisciplinary experience between the dental hygiene and medical technology programs at Marquette University. It was designed, in part, to familiarize dental hygiene students with the medical technology profession. Comments solicited from students on the final evaluation form indicated that this pilot project was highly successful and met the objectives. Affective, multiple-choice questions on pretests and posttests showed a positive change in attitude, but this change was not statistically significant. Possible reasons for this are discussed. Benefits of this pilot project were an improved understanding of medical technology on the part of the dental hygiene students, enhanced interdepartmental communication, and plans to develop a reciprocal interdisciplinary experience for the medical technology students. It is hoped that this pilot project will serve as a stimulus for similar experiences among other health science programs

Micromobility evolution and expansion: Understanding how docked and dockless bikesharing models complement and compete – A case study of San Francisco

Shared micromobility – the shared use of bicycles, scooters, or other low-speed modes – is an innovative transportation strategy growing across the United States that includes various service models such as docked, dockless, and e-bike service models. This research focuses on understanding how docked bikesharing and dockless e-bikesharing models complement and compete with respect to user travel behaviors. To inform our analysis, we used two datasets from February 2018 of Ford GoBike (docked) and JUMP (dockless electric) bikesharing trips in San Francisco. We employed three methodological approaches: 1) travel behavior analysis, 2) discrete choice analysis with a destination choice model, and 3) geospatial suitability analysis based on the Spatial Temporal Economic Physiological Social (STEPS) to Transportation Equity framework. We found that dockless e-bikesharing trips were longer in distance and duration than docked trips. The average JUMP trip was about a third longer in distance and about twice as long in duration than the average GoBike trip. JUMP users were far less sensitive to estimated total elevation gain than were GoBike users, making trips with total elevation gain about three times larger than those of GoBike users, on average. The JUMP system achieved greater usage rates than GoBike, with 0.8 more daily trips per bike and 2.3 more miles traveled on each bike per day, on average. The destination choice model results suggest that JUMP users traveled to lower-density destinations, and GoBike users were largely traveling to dense employment areas. Bike rack density was a significant positive factor for JUMP users. The location of GoBike docking stations may attract users and/or be well-placed to the destination preferences of users. The STEPS-based bikeability analysis revealed opportunities for the expansion of both bikesharing systems in areas of the city where high-job density and bike facility availability converge with older resident populations

Ionized Gas Kinematics at High Resolution IV: Star Formation and a Rotating Core in the Medusa (NGC 4194)

NGC 4194 is a post-merger starburst known as The Medusa for its striking tidal features. We present here a detailed study of the structure and kinematics of ionized gas in the central 0.65 kpc of the Medusa. The data include radio continuum maps with resolution up to 0.18\arcsec (35 pc) and a $12.8\mu$m [NeII] data cube with spectral resolution $\sim4$\kms: the first {\it high resolution, extinction-free} observations of this remarkable object. The ionized gas has the kinematic signature of a core in solid-body rotation. The starburst has formed a complex of bright compact \HII~regions, probably excited by deeply embedded super star clusters, but none of these sources is a convincing candidate for a galactic nucleus. The nuclei of the merger partners that created the Medusa have not yet been identified.Comment: to appear in Ap