The Algebra of Strand Splitting. II. A Presentation for the Braid Group on One Strand

Presentations are computed for a braided version BV of Thompson's group V and for V itself showing that there is an Artin group/Coxeter group relation between them. The presentation for V is obtained from that for BV by declaring all that all generators are involutions.Comment: 15 page

The Algebra of Strand Splitting. I. A Braided Version of Thompson's Group V

We construct a braided version of Thompson's group V.Comment: 27 page

Bicycle Handlebar Width Does Not Affect Spirometry, Ventilation, or Gas Exchange

Bicycle fit may affect comfort, aerodynamics, efficiency, ventilation, and power generation. Handlebars determine how the rider interacts with the bicycle. A wide range of handlebar widths are commercially available, but it is unclear if the resultant position affects lung function, ventilation, gas exchange, or efficiency. PURPOSE We aimed to measure the effects of handlebar widths on ventilation, gas exchange, spirometry, and comfort during moderate constant power exercise. METHODS Twenty-four recreationally active adults completed the study (32 ± 5 yrs., 175 ± 9 cm, 74 ± 12 kg, 8 women, 16 men). Participants completed three moderate constant power bouts of exercise on a cycle ergometer (Lode Excalibur PFM) while using handlebars set equivalent to, or ± 4cm in width to the participant shoulder width. We used a one-way RMANOVA to compare the three handlebar widths. RESULTS There was no difference in gas exchange and ventilation between the three handlebar widths: V̇O2 (F[2, 23] = 0.99, p = 0.38), V̇CO2 (F[1.47, 23] = 0.39, p = 0.62), V̇E (F[2, 23] = 0.53, p = 0.59], VT (F[2, 23] = 0.44, p = 0.65], fBr (F[2, 23] = 0.17, p = 0.84], PetO2(F[2, 23] = 0.45, p = 0.64), PetCO2 (F[2, 23] = 0.25, p=0.78]. Similarly, there were no differences in inspiratory capacity during the bout (F[1.49, 22] = 1.34, p = 0.27) or any spirometry variables immediately following exercise: FVC (F[1.43, 22] = 0.88, p = 0.39], FEV1 (F[2, 22] = 0.30, p = 0.74], FEV1/FVC (F[2, 22] = 0.18, p = 0.84], PEF (F[2, 22] = 0.14, p = 0.87]. There was no difference in the overall comfort (F[2, 23] = 0.90, p = 0.41] or shoulder discomfort (F [2, 23] = 0.90, p = 0.42). CONCLUSIONS Bicycle handlebar widths within 4 cm shoulder width do not result in changes to ventilation, gas exchange, efficiency, spirometry, or comfort during moderate power cycling exercise. Within the limits of rider preference, comfort, and safety, handlebar width can be adjusted substantially for aerodynamic purposes without affecting rider physiology

Improving SRAM FPGA Radiation Reliability Through Low-Level TMR Implementation

Mitigation techniques, such as TMR with repair, are used to reduce the negative effects of radiation on FPGAs deployed in space environments. While these techniques increase the robustness of the device, there is still room for improvement in the range of 100 to 1,000x. These improvements can be realized through the low-level implementation of the placement and routing on the device. This work has implemented a wide variety of techniques to realize these gains, achieving an overall improvement of 57,443x through fault-injection testing and an improvement of 350x in radiation testing

Altered thermoregulation in the iguana disposaurus dorsalis following exercise

1. 1.|Seven desert iguanas ran on a motorized treadmill for 20-min periods. Before, during and after exercise, the iguanas were in a thermal gradient which allowed them to thermoregulate behaviourally.2. 2.|For several hours following exercise, the iguanas selected warmer ambient temperatures, resulting in small, but statistically significant, increases in body temperature.3. 3.|The increases in temperature were proportional to the exercise intensity.4. 4.|These changes were not observed if exercised was preceded by administration of the antipyretic drug, sodium salicylate.5. 5.|These data support the hypothesis that exercise causes a change in central thermoregulatory control which may be similar to fever caused by infection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25757/1/0000318.pd

Elementary amenable subgroups of R. Thompson's group F

The subgroup structure of Thompson's group F is not yet fully understood. The group F is a subgroup of the group PL(I) of orientation preserving, piecewise linear self homeomorphisms of the unit interval and this larger group thus also has a poorly understood subgroup structure. It is reasonable to guess that F is the "only" subgroup of PL(I) that is not elementary amenable. In this paper, we explore the complexity of the elementary amenable subgroups of F in an attempt to understand the boundary between the elementary amenable subgroups and the non-elementary amenable. We construct an example of an elementary amenable subgroup up to class (height) omega squared, where omega is the first infinite ordinal.Comment: 20 page

Structurally Complex Osteosarcoma Genomes Exhibit Limited Heterogeneity within Individual Tumors and across Evolutionary Time

Osteosarcoma is an aggressive malignancy characterized by high genomic complexity. Identification of few recurrent mutations in protein coding genes suggests that somatic copy-number aberrations (SCNA) are the genetic drivers of disease. Models around genomic instability conflict-it is unclear whether osteosarcomas result from pervasive ongoing clonal evolution with continuous optimization of the fitness landscape or an early catastrophic event followed by stable maintenance of an abnormal genome. We address this question by investigating SCNAs in >12,000 tumor cells obtained from human osteosarcomas using single-cell DNA sequencing, with a degree of precision and accuracy not possible when inferring single-cell states using bulk sequencing. Using the CHISEL algorithm, we inferred allele- and haplotype-specific SCNAs from this whole-genome single-cell DNA sequencing data. Surprisingly, despite extensive structural complexity, these tumors exhibit a high degree of cell-cell homogeneity with little subclonal diversification. Longitudinal analysis of patient samples obtained at distant therapeutic timepoints (diagnosis, relapse) demonstrated remarkable conservation of SCNA profiles over tumor evolution. Phylogenetic analysis suggests that the majority of SCNAs were acquired early in the oncogenic process, with relatively few structure-altering events arising in response to therapy or during adaptation to growth in metastatic tissues. These data further support the emerging hypothesis that early catastrophic events, rather than sustained genomic instability, give rise to structural complexity, which is then preserved over long periods of tumor developmental time. SIGNIFICANCE: Chromosomally complex tumors are often described as genomically unstable. However, determining whether complexity arises from remote time-limited events that give rise to structural alterations or a progressive accumulation of structural events in persistently unstable tumors has implications for diagnosis, biomarker assessment, mechanisms of treatment resistance, and represents a conceptual advance in our understanding of intratumoral heterogeneity and tumor evolution

The Lyman Alpha Reference Sample. VIII. Characterizing Lyman-Alpha Scattering in Nearby Galaxies

We examine the dust geometry and Ly{\alpha} scattering in the galaxies of the Lyman Alpha Reference Sample (LARS), a set of 14 nearby (0.02 < $z$ < 0.2) Ly{\alpha} emitting and starbursting systems with Hubble Space Telescope Ly{\alpha}, H{\alpha}, and H{\beta} imaging. We find that the global dust properties determined by line ratios are consistent with other studies, with some of the LARS galaxies exhibiting clumpy dust media while others of them show significantly lower Ly{\alpha} emission compared to their Balmer decrement. With the LARS imaging, we present Ly{\alpha}/H{\alpha} and H{\alpha}/H{\beta} maps with spatial resolutions as low as $\sim$ 40 pc, and use these data to show that in most galaxies, the dust geometry is best modeled by three distinct regions: a central core where dust acts as a screen, an annulus where dust is distributed in clumps, and an outer envelope where Ly{\alpha} photons only scatter. We show that the dust that affects the escape of Ly{\alpha} is more restricted to the galaxies' central regions, while the larger Ly{\alpha} halos are generated by scattering at large radii. We present an empirical modeling technique to quantify how much Ly{\alpha} scatters in the halo, and find that this "characteristic" scattering distance correlates with the measured size of the Ly{\alpha} halo. We note that there exists a slight anti-correlation between the scattering distance of Ly{\alpha} and global dust properties.Comment: 32 pages, 51 figures, accepted to Ap