Showing 2001 - 2010 of 2039 Items
Date: 2001-01-01
Creator: B. Zorina Khan
Kenneth L. Sokoloff
Access: Open access
Date: 1992-01-01
Creator: D. S. Akerib
B. Barish
M. Chadha
D. F. Cowen
G., Eigen
J. S. Miller
J. Urheim
A. J. Weinstein
D. Acosta
G. Masek
B. Ong
H. Paar
M. Sivertz
A. Bean
J. Gronberg
R. Kutschke
S. Menary
R. J. Morrison
H. N. Nelson
J. D. Richman
H. Tajima
D. Schmidt
D. Sperka
M. S. Witherell
M. Procario
S. Yang
M. Daoudi
W. T. Ford
D. R. Johnson
K. Lingel
M. Lohner
Access: Open access
- The tau lepton electron branching fraction has been measured with the CLEO II detector at the Cornell Electron Storage Ring as Be=0.17490.00140.0022, with the first error statistical and the second systematic. The measurement involves counting electron-positron annihilation events in which both taus decay to electrons, and normalizing to the number of tau-pair decays expected from the measured luminosity. Detected photons in these events constitute a definitive observation of tau decay radiation. © 1992 The American Physical Society.
Date: 2015-12-01
Creator: Andrew E. Christie
Megan Chi
Tess J. Lameyer
Micah G. Pascual
Devlin N., Shea
Meredith E. Stanhope
David J. Schulz
Patsy S. Dickinson
Access: Open access
- Peptides are the largest and most diverse class of molecules used for neurochemical communication, playing key roles in the control of essentially all aspects of physiology and behavior. The American lobster, Homarus americanus, is a crustacean of commercial and biomedical importance; lobster growth and reproduction are under neuropeptidergic control, and portions of the lobster nervous system serve as models for understanding the general principles underlying rhythmic motor behavior (including peptidergic neuromodulation). While a number of neuropeptides have been identified from H. americanus, and the effects of some have been investigated at the cellular/systems levels, little is currently known about the molecular components of neuropeptidergic signaling in the lobster. Here, a H. americanus neural transcriptome was generated and mined for sequences encoding putative peptide precursors and receptors; 35 precursor- and 41 receptor-encoding transcripts were identified. We predicted 194 distinct neuropeptides from the deduced precursor proteins, including members of the adipokinetic hormone-corazonin-like peptide, allatostatin A, allatostatin C, bursicon, CCHamide, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone (CHH), CHH precursor-related peptide, diuretic hormone 31, diuretic hormone 44, eclosion hormone, FLRFamide, GSEFLamide, insulin-like peptide, intocin, leucokinin, myosuppressin, neuroparsin, neuropeptide F, orcokinin, pigment dispersing hormone, proctolin, pyrokinin, SIFamide, sulfakinin and tachykinin-related peptide families. While some of the predicted peptides are known H. americanus isoforms, most are novel identifications, more than doubling the extant lobster neuropeptidome. The deduced receptor proteins are the first descriptions of H. americanus neuropeptide receptors, and include ones for most of the peptide groups mentioned earlier, as well as those for ecdysistriggering hormone, red pigment concentrating hormone and short neuropeptide F. Multiple receptors were identified for most peptide families. These data represent the most complete description of the molecular underpinnings of peptidergic signaling in H. americanus, and will serve as a foundation for future gene-based studies of neuropeptidergic control in the lobster.
Date: 2015-09-01
Creator: Patsy S. Dickinson
Anirudh Sreekrishnan
Molly A. Kwiatkowski
Andrew E. Christie
Access: Open access
- Although the crustacean heart is modulated by a large number of peptides and amines, few of these molecules have been localized to the cardiac ganglion itself; most appear to reach the cardiac ganglion only by hormonal routes. Immunohistochemistry in the American lobster Homarus americanus indicates that pyrokinins are present not only in neuroendocrine organs ( pericardial organ and sinus gland), but also in the cardiac ganglion itself, where pyrokinin-positive terminals were found in the pacemaker cell region, as well as surrounding the motor neurons. Surprisingly, the single pyrokinin peptide identified from H. americanus, FSPRLamide, which consists solely of the conserved FXPRLamide residues that characterize pyrokinins, did not alter the activity of the cardiac neuromuscular system. However, a pyrokinin from the shrimp Litopenaeus vannamei [ADFAFNPRLamide, also known as Penaeus vannamei pyrokinin 2 (PevPK2)] increased both the frequency and amplitude of heart contractions when perfused through the isolated whole heart. None of the other crustacean pyrokinins tested (another from L. vannamei and two from the crab Cancer borealis) had any effect on the lobster heart. Similarly, altering the PevPK2 sequence either by truncation or by the substitution of single amino acids resulted in much lower or no activity in all cases; only the conservative substitution of serine for alanine at position 1 resulted in any activity on the heart. Thus, in contrast to other systems (cockroach and crab) in which all tested pyrokinins elicit similar bioactivities, activation of the pyrokinin receptor in the lobster heart appears to be highly isoform specific.
Date: 1991-01-01
Creator: Y. Kubota
J. K. Nelson
D. Perticone
R. Poling
S., Schrenk
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
Access: Open access
- The spin alignment of D*+ mesons produced in e+e- annihilation at s=10.5 GeV is obtained from a study of the angular distribution of the decay D*+D0+. The alignment is studied as a function of momentum and compared to theoretical predictions. We find an average value of the spin alignment parameter of =0.040.020.01. We obtain a model-dependent measurement of the probability of producing a vector particle PV=0.770.020.01 for D mesons. © 1991 The American Physical Society.
Date: 1990-01-01
Creator: P. Avery
D. Besson
L. Garren
J. Yelton
K., Kinoshita
F. M. Pipkin
M. Procario
Richard Wilson
J. Wolinski
D. Xiao
Y. Zhu
R. Ammar
P. Baringer
D. Coppage
R. Davis
P. Haas
M. Kelly
N. Kwak
Ha Lam
S. Ro
Y. Kubota
J. K. Nelson
D. Perticone
R. Poling
R. Fulton
T. Jensen
D. R. Johnson
H. Kagan
R. Kass
F. Morrow
J. Whitmore
Access: Open access
- We report a measurement of polarization in the two-body decay c+, in nonresonant e+e- interactions from data taken with the CLEO detector. Using these data we have determined the parity-violating asymmetry decay parameter c to be -1.0-0.0+0.4. We see no evidence for significant c+ polarization. © 1990 The American Physical Society.
Date: 2009-04-15
Creator: Patsy S. Dickinson
Teerawat Wiwatpanit
Emily R. Gabranski
Rachel J. Ackerman
Jake S., Stevens
Christopher R. Cashman
Elizabeth A. Stemmler
Andrew E. Christie
Access: Open access
- The allatostatins comprise three structurally distinct peptide families that regulate juvenile hormone production by the insect corpora allata. A-type family members contain the C-terminal motif -YXFGLamide and have been found in species from numerous arthropod taxa. Members of the B-type family exhibit a -WX6Wamide C-terminus and, like the A-type peptides, appear to be broadly conserved within the Arthropoda. By contrast, members of the C-type family, typified by the unblocked C-terminus -PISCF, a pyroglutamine blocked N-terminus, and a disulfide bridge between two internal Cys residues, have only been found in holometabolous insects, i.e. lepidopterans and dipterans. Here, using transcriptomics, we have identified SYWKQCAFNAVSCFamide (disulfide bridging predicted between the two Cys residues), a known honeybee and water flea C-typelike peptide, from the American lobster Homarus americanus (infraorder Astacidea). Using matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS), a mass corresponding to that of SYWKQCAFNAVSCFamide was detected in the H. americanus brain, supporting the existence of this peptide and its theorized structure. Furthermore, SYWKQCAFNAVSCFamide was detected by MALDI-FTMS in neural tissues from five additional astacideans as well as 19 members of four other decapod infraorders (i.e. Achelata, Anomura, Brachyura and Thalassinidea), suggesting that it is a broadly conserved decapod peptide. In H. americanus, SYWKQCAFNAVSCFamide is capable of modulating the output of both the pyloric circuit of the stomatogastric nervous system and the heart. This is the first demonstration of bioactivity for this peptide in any species.
Date: 2019-09-21
Creator: Kenneth A. Dennison
Thomas W. Baumgarte
Stuart L. Shapiro
Access: Open access
- The ‘direct collapse’ scenario has emerged as a promising evolutionary track for the formation of supermassive black holes early in the Universe. In an idealized version of such a scenario, a uniformly rotating supermassive star spinning at the mass-shedding (Keplerian) limit collapses gravitationally after it reaches a critical configuration. Under the assumption that the gas is dominated by radiation pressure, this critical configuration is characterized by unique values of the dimensionless parameters J/M2 and Rp/M, where J is the angular momentum, Rp the polar radius, and M the mass. Motivated by a previous perturbative treatment, we adopt a fully non-linear approach to evaluate the effects of gas pressure on these dimensionless parameters for a large range of masses. We find that gas pressure has a significant effect on the critical configuration even for stellar masses as large as M ~ 106 MO. We also calibrate two approximate treatments of the gas pressure perturbation in a comparison with the exact treatment, and find that one commonly used approximation in particular results in increasing deviations from the exact treatment as the mass decreases, and the effects of gas pressure increase. The other approximation, however, proves to be quite robust for all masses M >~ 104 MO.
Date: 2001-01-01
Creator: Patsy S. Dickinson
Jane Hauptman
John Hetling
Anand Mahadevan
Access: Open access
- The neuropeptide red pigment concentrating hormone (RPCH), which we have previously shown to activate the cardiac sac motor pattern and lead to a conjoint gastric mill-cardiac sac pattern in the spiny lobster Panulirus, also activates and modulates the pyloric pattern. Like the activity of gastric mill neurons in RPCH, the pattern of activity in the pyloric neurons is considerably more complex than that seen in control saline. This reflects the influence of the cardiac sac motor pattern, and particularly the upstream inferior ventricular (IV) neurons, on many of the pyloric neurons. RPCH intensifies this interaction by increasing the strength of the synaptic connections between the IV neurons and their targets in the stomatogastric ganglion. At the same time, RPCH enhances postinhibitory rebound in the lateral pyloric (LP) neuron. Taken together, these factors largely explain the complex pyloric pattern recorded in RPCH in Panulirus.
Date: 2012-10-26
Creator: Kenneth A. Dennison
Thomas W. Baumgarte
Access: Open access
- Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In particular, this method has been proposed as a tool for interpreting results from numerical binary black hole simulations, providing a deeper insight into the physical processes governing the merger of black holes and the emission of gravitational radiation. Here we apply this approach to approximate but analytical initial data for both single boosted and binary black holes. These perturbative data become exact in the limit of small boost or large binary separation. We hope that these calculations will provide additional insight into the properties of tendex and vortex fields and will form a useful test for future numerical calculations. © 2012 American Physical Society.