Showing 1571 - 1580 of 5709 Items
Effect of differential rotation on the maximum mass of neutron stars: Realistic nuclear equations of state
Date: 2004-01-01
Creator: I.A. Morrison, T.W. Baumgarte, S.L. Shapiro
Access: Open access
General relativistic magnetohydrodynamics for the numerical construction of dynamical spacetimes
Date: 2003-01-01
Creator: T.W. Baumgarte, S.L. Shapiro
Access: Open access
Neurotransmitter interactions in the stomatogastric system of the spiny lobster: One peptide alters the response of a central pattern generator to a second peptide
Date: 1997-01-01
Creator: Patsy S. Dickinson, Wesley P. Fairfield, John R. Hetling, Jane Hauptman
Access: Open access
- Two of the peptides found in the stomatogastric nervous system of the spiny lobster. Panulirus interruptus, interacted to modulate the activity of the cardiac sac motor pattern. In the isolated stomatogastric ganglion, red- pigment-concentrating hormone (RPCH), but not proctolin, activated the bursting activity in the inferior ventricular (IV) neurons that drives the cardiac sac pattern. The cardiac sac pattern normally ceased within 15 min after the end of RPCH superfusion. However, when proctolin was applied within a few minutes of that time, it was likewise able to induce cardiac sac activity. Similarly, proctolin applied together with subthreshold RPCH induced cardiac sac bursting. The amplitude of the excitatory postsynaptic potentials from the IV neurons to the cardiac sac dilator neuron CD2 (1 of the 2 major motor neurons in the cardiac sac system) was potentiated in the presence of both proctolin and RPCH. The potentiation in RPCH was much greater than in proctolin alone. However, the potentiation in proctolin after RPCH was equivalent to that recorded in RPCH alone. Although we do not yet understand the mechanisms for these interactions of the two modulators, this study provides an example of one factor that can determine the 'state' of the system that is critical in determining the effect of a modulator that is 'state dependent,' and it provides evidence for yet another level of flexibility in the motor output of this system.
“One of Folly’s Failures”: Plessy v. Ferguson (1896) and the Decline of the Thirteenth Amendment This record is embargoed.
- Embargo End Date: 2025-05-14
Date: 2020-01-01
Creator: Grace Ann Fenwick
Access: Embargoed
Bowdoin College Catalogue (1909-1910)
Date: 1910-01-01
Access: Open access
- Bowdoin College Bulletin no. 26
On the nature of eγ and non-vanishing of derivatives of L-series at s=1/2
Date: 2014-04-30
Creator: M. Ram Murty, Naomi Tanabe
Access: Open access
- In 2011, M.R. Murty and V.K. Murty [10] proved that if L(s, χD) is the Dirichlet L-series attached a quadratic character χD, and L'(1, χD)=0, then eγ is transcendental. This paper investigates such phenomena in wider collections of L-functions, with a special emphasis on Artin L-functions. Instead of s=1, we consider s=1/2. More precisely, we prove thatexp (L'(1/2,χ)L(1/2,χ)-αγ) is transcendental with some rational number α. In particular, if we have L(1/2, χ)≠0 and L'(1/2, χ)=0 for some Artin L-series, we deduce the transcendence of eγ.
Mechanisms underlying variable responses to the neuropeptide C-type allatostatin (AST-C) across isoforms and among individuals in the American lobster, Homarus americanus
Date: 2020-01-01
Creator: Audrey J. Muscato
Access: Open access
- Central pattern generators (CPGs) produce patterned outputs independent of sensory input. The cardiac neuromuscular system of the American lobster (Homarus americanus) is driven by a CPG called the cardiac ganglion (CG), which is composed of nine neurons, making it a model system of study. Modulation of CPGs allows for functional flexibility. One neuropeptide family that modulates the CG is C-type allatostatin (AST-C I-III). Previous research has shown variation in the responses of the CG across the three isoforms and among individuals. First, we investigated why AST-C I and III elicit responses that are more similar to each other than they are to the responses elicited by AST-C II. We hypothesized that an amino acid difference in the conserved sequence was responsible for the observed variation in responses. We synthesized isoforms of AST-C that replaced the endogenous amino acid and recorded responses to these isoforms. The identity of one particular amino acid in the conserved sequence seems to be responsible for variations in responses in frequency. Next, we focused on variation among individuals in their responses to AST-C I and III. We hypothesized that the mechanism behind this individual variation is differential expression of AST-C receptors and/or their downstream targets. We recorded physiological responses of the cardiac system to AST-C and then sequenced CG RNA from the same lobsters. Differential expression of one of the AST-C receptors and a number of downstream factors is correlated with physiological response. These findings inspire further experimentation investigating molt cycle as the underlying cause.
Mercury in the snow and firn at Summit Station, Central Greenland, and implications for the study of past atmospheric mercury levels
Date: 2008-06-30
Creator: X. Faïn, C. P. Ferrari, A. Dommergue, M. Albert, M., Battle, L. Arnaud, J. M. Barnola, W. Cairns, C. Barbante, C. Boutron
Access: Open access
- Gaseous Elemental Mercury (Hg° or GEM) was investigated at Summit Station, Greenland, in the interstitial air extracted from the perennial snowpack (firn) at depths ranging from the surface to 30 m, during summer 2005 and spring 2006. Photolytic production and destruction of Hg° were observed close to the snow surface during summer 2005 and spring 2006, and we observed dark oxidation of GEM up to 270 cm depth in June 2006. Photochemical transformation of gaseous elemental mercury resulted in diel variations in the concentrations of this gas in the near-surface interstitial air, but destruction of Hg° was predominant in June, and production was the main process in July. This seasonal evolution of the chemical mechanisms involving gaseous elemental mercury produces a signal that propagates downward through the firn air, but is unobservably small below 15 m in depth. As a consequence, multi-annual averaged records of GEM concentration should be well preserved in deep firn air at depths below 15 m, and available for the reconstruction of the past atmospheric history of GEM over the last decades.
ELMO, A Possible Pectin Biosynthesis Scaffold Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2023-01-01
Creator: Nuoya (Laura) Yang
Access: Access restricted to the Bowdoin Community