Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Two-Neutron Sequential Decay Of 24o, M. D. Jones, N. Frank, T. Baumann, J. Brett, J. Bullaro, P. A. Deyoung, J.E. Finck, K. Hammerton, J. Hinnefeld, Z. Kohley, A. N. Kuchera, J. Pereira, A. Rabeh, W. F. Rogers, J. K. Smith, A. Spyrou, Sharon L. Stephenson, K. Stiefel, M. Tuttle-Timm, R. G.T. Zegers, M. Thoennessen
Two-Neutron Sequential Decay Of 24o, M. D. Jones, N. Frank, T. Baumann, J. Brett, J. Bullaro, P. A. Deyoung, J.E. Finck, K. Hammerton, J. Hinnefeld, Z. Kohley, A. N. Kuchera, J. Pereira, A. Rabeh, W. F. Rogers, J. K. Smith, A. Spyrou, Sharon L. Stephenson, K. Stiefel, M. Tuttle-Timm, R. G.T. Zegers, M. Thoennessen
Physics and Astronomy Faculty Publications
A two-neutron unbound excited state of 24O was populated through a (d,d ) reaction at 83.4 MeV/nucleon. A state at E = 715 ± 110 (stat) ± 45 (sys) keV with a width of < 2 MeV was observed above the two-neutron separation energy placing it at 7.65 ± 0.2 MeV with respect to the ground state. Three-body correlations for the decay of 24O → 22O + 2n show clear evidence of a sequential decay through an intermediate state in 23O. Neither a di-neutron nor phase-space model for the three-body breakup were able to describe these correlations.
Population Of 13be In A Nucleon Exchange Reaction, B. R. Marks, P. A. Deyoung, J. K. Smith, T. Baumann, J. Brown, N. Frank, J. Hinnefeld, M. Hoffman, M. D. Jones, Z. Kohley, A. N. Kuchera, B. Luther, A. Spyrou, Sharon L. Stephenson, C. Sullivan, M. Thoennessen, N. Viscariello, S. J. Williams
Population Of 13be In A Nucleon Exchange Reaction, B. R. Marks, P. A. Deyoung, J. K. Smith, T. Baumann, J. Brown, N. Frank, J. Hinnefeld, M. Hoffman, M. D. Jones, Z. Kohley, A. N. Kuchera, B. Luther, A. Spyrou, Sharon L. Stephenson, C. Sullivan, M. Thoennessen, N. Viscariello, S. J. Williams
Physics and Astronomy Faculty Publications
The neutron-unbound nucleus Be13 was populated with a nucleon exchange reaction from a 71 MeV/u secondary B13 beam. The decay-energy spectrum was reconstructed using invariant mass spectroscopy based on Be12 fragments in coincidence with neutrons. The data could be described with an s-wave resonance at Er=0.73(9)MeV with a width of Γr=1.98(34)MeVand a d-wave resonance at Er=2.56(13)MeV with a width of Γr=2.29(73)MeV. The observed spectral shape is consistent with previous one-proton removal reaction measurements from B14.
Intrinsic Fluctuations And Driven Response Of Insect Swarms, Rui Ni, James G. Puckett, Eric R. Dufresne, Nicholas T. Ouellette
Intrinsic Fluctuations And Driven Response Of Insect Swarms, Rui Ni, James G. Puckett, Eric R. Dufresne, Nicholas T. Ouellette
Physics and Astronomy Faculty Publications
Animals of all sizes form groups, as acting together can convey advantages over acting alone; thus, collective animal behavior has been identified as a promising template for designing engineered systems. However, models and observations have focused predominantly on characterizing the overall group morphology, and often focus on highly ordered groups such as bird flocks. We instead study a disorganized aggregation (an insect mating swarm), and compare its natural fluctuations with the group-level response to an external stimulus. We quantify the swarm’s frequency-dependent linear response and its spectrum of intrinsic fluctuations, and show that the ratio of these two quantities has …
Time-Frequency Analysis Reveals Pairwise Interactions In Insect Swarms, James G. Puckett, Rui Ni, Nicholas T. Ouellette
Time-Frequency Analysis Reveals Pairwise Interactions In Insect Swarms, James G. Puckett, Rui Ni, Nicholas T. Ouellette
Physics and Astronomy Faculty Publications
The macroscopic emergent behavior of social animal groups is a classic example of dynamical self-organization, and is thought to arise from the local interactions between individuals. Determining these interactions from empirical data sets of real animal groups, however, is challenging. Using multicamera imaging and tracking, we studied the motion of individual flying midges in laboratory mating swarms. By performing a time-frequency analysis of the midge trajectories, we show that the midge behavior can be segmented into two distinct modes: one that is independent and composed of low-frequency maneuvers, and one that consists of higher-frequency nearly harmonic oscillations conducted in synchrony …
A Slow Neutron Polarimeter For The Measurement Of Parity-Odd Neutron Rotary Power, W. M. Snow, E. Anderson, L. Barron-Palos, C. D. Bass, T. D. Bass, Bret E. Crawford, C. Crawford, J. M. Dawkins, D. Esposito, J. Fry, H. Gardiner, K. Gan, C. Haddock, B. R. Heckel, A. T. Holley, J. C. Horton, C. Huffer, J. Lieffers, D. Luo, M. Maldonado-Velazquez, D. M. Markoff, A. M. Micherdzinska, H. P. Mumm, J. S. Nico, M. Sarsour, S. Santra, E. I. Sharapov, H. E. Swanson, S. B. Walbridge, V. Zhumabekova
A Slow Neutron Polarimeter For The Measurement Of Parity-Odd Neutron Rotary Power, W. M. Snow, E. Anderson, L. Barron-Palos, C. D. Bass, T. D. Bass, Bret E. Crawford, C. Crawford, J. M. Dawkins, D. Esposito, J. Fry, H. Gardiner, K. Gan, C. Haddock, B. R. Heckel, A. T. Holley, J. C. Horton, C. Huffer, J. Lieffers, D. Luo, M. Maldonado-Velazquez, D. M. Markoff, A. M. Micherdzinska, H. P. Mumm, J. S. Nico, M. Sarsour, S. Santra, E. I. Sharapov, H. E. Swanson, S. B. Walbridge, V. Zhumabekova
Physics and Astronomy Faculty Publications
We present the design, description, calibration procedure, and an analysis of systematic effects for an apparatus designed to measure the rotation of the plane of polarization of a transversely polarized slow neutron beam as it passes through unpolarized matter. This device is the neutronoptical equivalent of a crossed polarizer/analyzer pair familiar from light optics. This apparatus has been used to search for parity violation in the interaction of polarized slow neutrons in matter. Given the brightness of existing slow neutron sources, this apparatus is capable ofmeasuring a neutron rotary power of dϕ/dz = 1 × 10−7 rad/m.
Quantitative Analysis Of Single-Molecule Force Spectroscopy On Folded Chromatin Fibers, He Meng, Kurt Andresen, John Van Noort
Quantitative Analysis Of Single-Molecule Force Spectroscopy On Folded Chromatin Fibers, He Meng, Kurt Andresen, John Van Noort
Physics and Astronomy Faculty Publications
Single-molecule techniques allow for picoNewton manipulation and nanometer accuracy measurements of single chromatin fibers. However, the complexity of the data, the heterogeneity of the composition of individual fibers and the relatively large fluctuations in extension of the fibers complicate a structural interpretation of such force-extension curves. Here we introduce a statistical mechanics model that quantitatively describes the extension of individual fibers in response to force on a per nucleosome basis. Four nucleosome conformations can be distinguished when pulling a chromatin fiber apart. A novel, transient conformation is introduced that coexists with single wrapped nucleosomes between 3 and 7 pN. Comparison …