Showing 4471 - 4480 of 5709 Items
Date: 2024-01-01
Creator: Karin van Hassel
Access: Open access
- The cardiac ganglion (CG) is a central pattern generator, a neural network that, when activated, produces patterned motor outputs such as breathing and walking. The CG induces the heart contractions of the American lobster, Homarus americanus, making the lobster heart neurogenic. In the American lobster, the CG is made up of nine neurons: four premotor pacemaker neurons that send signals to five motor neurons, causing bursts of action potentials from the motor neurons. These bursts cause cardiac muscle contractions that vary in strength based on the burst duration, frequency, and pattern. The activity of the CG is modulated by feedback pathways and neuromodulators, allowing for flexibility in the CG’s motor output and appropriate responses to changes in the animal’s environment. Two feedback pathways modulate the CG motor output, the excitatory cardiac muscle stretch and inhibitory nitric oxide feedback pathways. Despite our knowledge of the modulation of the CG by feedback pathways and neuromodulators separately, little is known about how neuromodulators influence the sensory feedback response to cardiac muscle stretch. I found one neuromodulator to modulate each phase of the stretch response differently, one neuromodulator to generally not affect the stretch response, and three neuromodulators to suppress the stretch response. These results suggest neuromodulators can act to produce flexibility in a CPG’s motor output, allowing the system to respond appropriately to changes in an organism’s environment, and allow for variation in CPG responses to different stimuli.
Date: 2017-05-01
Creator: Xuanming Guo
Access: Open access
- This study uses an event study framework to find the relationship between ownership concentration and project value. I find that project value first increases with ownership concentration when block size, the percentage ownership of the largest blockholder, is smaller than 10%, then declines with ownership concentration when block size gets larger, and finally rises again when block size exceeds 30%. However, my research only suggests an ambiguous relationship between ownership concentration and firm value. Additionally, ownership concentration seems to affect both the timing of market responses and the market’s interpretation of large investment projects.
Date: 2014-05-01
Creator: Marissa C Rosenthal
Access: Access restricted to the Bowdoin Community
Date: 1975-01-01
Creator: William H. Barker
Access: Open access
- Let G be a connected semisimple Lie group with finite center and K a maximal compact subgroup. Denote (i) Harish-Chandra's Schwartz spaces by Cp(G)(0
Date: 1995-06-01
Creator: F. Montes de Oca, M. L. Zeeman
Access: Open access
- We generalise and unify some recent results about extinction in nth-order nonautonomous competitive Lotka-Volterra systems. For each r ≤ n, we show that if the coefficients are continuous, bounded by strictly positive constants, and satisfy certain inequalities, then any solution with strictly positive initial values has the property that n - r of its components vanish, whilst the remaining r components asymptotically approach a canonical solution of an r-dimensional restricted system. In other words, r of the species being modeled survive whilst the remaining n - r are driven to extinction. © 1995 Academic Press, Inc.
Date: 1993-01-01
Creator: M. Procario, S. Yang, R. Balest, K. Cho, M., Daoudi, W. T. Ford, D. R. Johnson, K. Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, D. Besson, T. E. Browder, D. G. Cassel, H. A. Cho, D. M. Coffman, P. S. Drell, R. Ehrlich, R. S. Galik, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, K. Honscheid, C. D. Jones, S. L. Jones
Access: Open access
- With the CLEO-II detector at the Cornell Electron Storage Ring, we have measured branching fractions for tau lepton decay into one-prong final states with multiple π0's Bhnπ0, normalized to the branching fraction for tau decay into one charged particle and a single π0. We find Bh2π0/Bhπ0=0. 345±0.006±0.016, Bh3π0/Bhπ0=0.041 ±0.003±0. 005, and Bh4π0/Bhπ0=0.006±0.002±0.002. © 1993 The American Physical Society.
Date: 1992-01-01
Creator: G. Crawford, R. Fulton, T. Jensen, D. R. Johnson, H., Kagan, R. Kass, R. Malchow, F. Morrow, J. Whitmore, P. Wilson, D. Bortoletto, D. Brown, J. Dominick, R. L. McIlwain, D. H. Miller, M. Modesitt, C. R. Ng, S. F. Schaffner, E. I. Shibata, I. P.J. Shipsey, M. Battle, H. Kroha, K. Sparks, E. H. Thorndike, C. H. Wang, M. S. Alam, I. J. Kim, W. C. Li, X. C. Lou, B. Nemati, V. Romero
Access: Open access
- Using the CLEO detector at the Cornell Electron Storage Ring, we observe B-meson decays to c+ and report on improved measurements of inclusive branching fractions and momentum spectra of other baryons. For the inclusive decay Bc+X with c+pK-+, we find that the product branching fraction B(Bc+X)B(c+pK-+)=(0.273±0.051±0.039)%. Our measured inclusive branching fractions to noncharmed baryons are B(BpX)=(8.0±0.5±0.3)%, B(BX)=(3.8±0.4±0.6)%, and B(B-X)=(0.27±0.05±0.04)%. From these rates and studies of baryon-lepton and baryon-antibaryon correlations in B decays, we have estimated the branching fraction B(Bc+X) to be (6.40.8±0.8)%. Combining these results, we calculate B(c+pK-) to be (4.3±1.0±0.8)%. © 1992 The American Physical Society.
Date: 1991-01-01
Creator: R. Ammar, P. Baringer, D. Coppage, R. Davis, P., Haas, M. Kelly, N. Kwak, H. Lam, S. Ro, Y. Kubota, J. K. Nelson, D. Perticone, R. Poling, S. Schrenk, G. Crawford, R. Fulton, T. Jensen, D. Johnson, H. Kagan, R. Kass, R. Malchow, F. Marrow, J. Whitmore, P. Wilson, D. Bortoletto, D. N. Brown, J. Dominick, R. L. McIlwain, D. H. Miller, M. Modesitt, C. R. Ng
Access: Open access
- CLEO has measured decay modes of the D0 and D+ into final states consisting of K's, s, K0's and 0's, using data taken with the CLEO detector at the Cornell Electron Storage Ring. We report new results on the decays of D0's into 4, K-K+-+, 0K+K-, 0K+-, K0K-+, 3KS0 and 0 together with some of their resonant substructure. We also present the first observation of the decay D00K+ and give limits on the doubly-Cabibbo-suppressed decays of the D0 into K+- and K+-+-. © 1991 The American Physical Society.