Showing 701 - 710 of 2040 Items
Measurement of the branching fraction scrB(τ-→h- →π0ντ)
Date: 1994-01-01
Creator: M. Artuso
M. Goldberg
D. He
N. Horwitz
R., Kennett
R. Mountain
G. C. Moneti
F. Muheim
Y. Mukhin
S. Playfer
Y. Rozen
S. Stone
M. Thulasidas
G. Vasseur
X. Xing
G. Zhu
J. Bartelt
S. E. Csorna
Z. Egyed
V. Jain
K. Kinoshita
B. Barish
M. Chadha
S. Chan
D. F. Cowen
G. Eigen
J. S. Miller
C. O'Grady
J. Urheim
A. J. Weinstein
D. Acosta
Access: Open access
- Using data from the CLEO II detector at the Cornell Electron Storage Ring, we measure scrB(τ-→h-π0ντ) where h- refers to either π- or K-. We use three different methods to measure this branching fraction. The combined result is scrB(τ-→h-π0ντ)=0.2587±0. 0012±0.0042, in good agreement with standard model predictions. © 1994 The American Physical Society.
Search for exclusive b→u semileptonic decays of B mesons
Date: 1993-01-01
Creator: 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
R. Ballest
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
Access: Open access
- Using a sample of 935 000 BB̄ pairs collected with the CLEO-II detector at the Cornell Electron Storage Ring, we have obtained upper limits on the branching ratios for the b→ul-ν̄ processes B-→ωl- ν̄, B-→ρ0l-ν̄, and B̄0→ρ+l-ν̄. The combined result using the relationships among the widths for these three modes is B(B-→ρ0l-ν̄)<(1.6-2.7)×10-4 at 90% C.L., where the range of values is due to model dependence of the detection efficiencies. These measurements yield the limits Vub/Vcb<0.08-0.13. © 1993 The American Physical Society.
Differential neuropeptide modulation of premotor and motor neurons in the lobster cardiac ganglion
Date: 2020-10-01
Creator: Emily R. Oleisky
Meredith E. Stanhope
J. Joe Hull
Andrew E. Christie
Patsy S., Dickinson
Access: Open access
- The American lobster, Homarus americanus, cardiac neuromuscular system is controlled by the cardiac ganglion (CG), a central pattern generator consisting of four premotor and five motor neurons. Here, we show that the premotor and motor neurons can establish independent bursting patterns when decoupled by a physical ligature. We also show that mRNA encoding myosuppressin, a cardioactive neuropeptide, is produced within the CG. We thus asked whether myosuppressin modulates the decoupled premotor and motor neurons, and if so, how this modulation might underlie the role(s) that these neurons play in myosuppressin's effects on ganglionic output. Although myosuppressin exerted dose-dependent effects on burst frequency and duration in both premotor and motor neurons in the intact CG, its effects on the ligatured ganglion were more complex, with different effects and thresholds on the two types of neurons. These data suggest that the motor neurons are more important in determining the changes in frequency of the CG elicited by low concentrations of myosuppressin, whereas the premotor neurons have a greater impact on changes elicited in burst duration. A single putative myosuppressin receptor (MSR-I) was previously described from the Homarus nervous system. We identified four additional putative MSRs (MSR-II-V) and investigated their individual distributions in the CG premotor and motor neurons using RT-PCR. Transcripts for only three receptors (MSR-II-IV) were amplified from the CG. Potential differential distributions of the receptors were observed between the premotor and motor neurons; these differences may contribute to the distinct physiological responses of the two neuron types to myosuppressin. NEW & NOTEWORTHY Premotor and motor neurons of the Homarus americanus cardiac ganglion (CG) are normally electrically and chemically coupled, and generate rhythmic bursting that drives cardiac contractions; we show that they can establish independent bursting patterns when physically decoupled by a ligature. The neuropeptide myosuppressin modulates different aspects of the bursting pattern in these neuron types to determine the overall modulation of the intact CG. Differential distribution of myosuppressin receptors may underlie the observed responses to myosuppressin.
High Cryptic Diversity across the Global Range of the Migratory Planktonic Copepods Pleuromamma piseki and P. gracilis
Date: 2013-10-22
Creator: Kristin M.K. Halbert
Erica Goetze
David B. Carlon
Access: Open access
- Although holoplankton are ocean drifters and exhibit high dispersal potential, a number of studies on single species are finding highly divergent genetic clades. These cryptic species complexes are important to discover and describe, as identification of common marine species is fundamental to understanding ecosystem dynamics. Here we investigate the global diversity within Pleuromamma piseki and P. gracilis, two dominant members of the migratory zooplankton assemblage in subtropical and tropical waters worldwide. Using DNA sequence data from the mitochondrial gene cytochrome c oxidase subunit II (mtCOII) from 522 specimens collected across the Pacific, Atlantic and Indian Oceans, we discover twelve well-resolved genetically distinct clades in this species complex (Bayesian posterior probabilities >0.7; 6.3-17% genetic divergence between clades). The morphologically described species P. piseki and P. gracilis did not form monophyletic groups, rather they were distributed throughout the phylogeny and sometimes co-occurred within well-resolved clades: this result suggests that morphological characters currently used for taxonomic identification of P. gracilis and P. piseki may be inaccurate as indicators of species' boundaries. Cryptic clades within the species complex ranged from being common to rare, and from cosmopolitan to highly restricted in distribution across the global ocean. These novel lineages appear to be ecologically divergent, with distinct biogeographic distributions across varied pelagic habitats. We hypothesize that these mtDNA lineages are distinct species and suggest that resolving their systematic status is important, given the ecological significance of the genus Pleuromamma in subtropical-tropical waters worldwide. © 2013 Halbert et al.
A 60 yr record of atmospheric carbon monoxide reconstructed from Greenland firn air
Date: 2013-08-19
Creator: V. V. Petrenko
P. Martinerie
P. Novelli
D. M. Etheridge
I., Levin
Z. Wang
T. Blunier
J. Chappellaz
J. Kaiser
P. Lang
L. P. Steele
S. Hammer
J. Mak
R. L. Langenfelds
J. Schwander
J. P. Severinghaus
E. Witrant
G. Petron
M. O. Battle
G. Forster
W. T. Sturges
J. F. Lamarque
K. Steffen
J. W.C. White
Access: Open access
- We present the first reconstruction of the Northern Hemisphere (NH) high latitude atmospheric carbon monoxide (CO) mole fraction from Greenland firn air. Firn air samples were collected at three deep ice core sites in Greenland (NGRIP in 2001, Summit in 2006 and NEEM in 2008). CO records from the three sites agree well with each other as well as with recent atmospheric measurements, indicating that CO is well preserved in the firn at these sites. CO atmospheric history was reconstructed back to the year 1950 from the measurements using a combination of two forward models of gas transport in firn and an inverse model. The reconstructed history suggests that Arctic CO in 1950 was 140-150 nmol mol-1, which is higher than today's values. CO mole fractions rose by 10-15 nmol mol-1 from 1950 to the 1970s and peaked in the 1970s or early 1980s, followed by a ≈ 30 nmol mol-1 decline to today's levels. We compare the CO history with the atmospheric histories of methane, light hydrocarbons, molecular hydrogen, CO stable isotopes and hydroxyl radicals (OH), as well as with published CO emission inventories and results of a historical run from a chemistry-transport model. We find that the reconstructed Greenland CO history cannot be reconciled with available emission inventories unless unrealistically large changes in OH are assumed. We argue that the available CO emission inventories strongly underestimate historical NH emissions, and fail to capture the emission decline starting in the late 1970s, which was most likely due to reduced emissions from road transportation in North America and Europe. © Author(s) 2013.
Measurement of the ratio B(D0'e)B(D0K-e+e)
Date: 1991-01-01
Creator: G. Crawford
R. Fulton
K. K. Gan
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
P. Kim
H. Kroha
K. Sparks
E. H. Thorndike
C. H. Wang
M. S. Alam
I. J. Kim
B. Nemati
V. Romero
Access: Open access
- Using the CLEO detector at the Cornell Electron Storage Ring, we have performed a direct measurement of the ratio of D0 semileptonic branching fractions into vector and pseudoscalar final states. We find B(D0K*-e+e)B(D0K-e+e)=0.510.180.06, in agreement with the ratio derived by the E691 experiment which compares D+ and D0 final states. We also set an upper limit on the ratio B(D0*0-e+e)B(D0K*-e+e)<0.64 at 90% confidence level. © 1991 The American Physical Society.
The moment of inertia of the binary pulsar J0737-3039A: Constraining the nuclear equation of state
Date: 2004-01-01
Creator: I.A. Morrison
T.W. Baumgarte
S.L. Shapiro
V.R. Pandharipande
Access: Open access
Molecular, mass spectral, and physiological analyses of orcokinins and orcokinin precursor-related peptides in the lobster Homarus americanus and the crayfish Procambarus clarkii
Date: 2009-02-01
Creator: Patsy S. Dickinson
Elizabeth A. Stemmler
Elizabeth E. Barton
Christopher R. Cashman
Noah P., Gardner
Szymon Rus
Henry R. Brennan
Timothy S. McClintock
Andrew E. Christie
Access: Open access
- Recently, cDNAs encoding prepro-orcokinins were cloned from the crayfish Procambarus clarkii; these cDNAs encode multiple copies of four orcokinin isoforms as well as several other peptides. Using the translated open reading frames of the P. clarkii transcripts as queries, five ESTs encoding American lobster Homarus americanus orthologs were identified via BLAST analysis. From these clones, three cDNAs, each encoding one of two distinct prepro-hormones, were characterized. Predicted processing of the deduced prepro-hormones would generate 13 peptides, 12 of which are conserved between the 2 precursors: the orcokinins NFDEIDRSGFGFN (3 copies), NFDEIDRSGFGFH (2 copies) and NFDEIDRSGFGFV (2 copies), FDAFTTGFGHN (an orcomyotropin-related peptide), SSEDMDRLGFGFN, GDY(SO3)DVYPE, VYGPRDIANLY and SAE. Additionally, one of two longer peptides (GPIKVRFLSAIFIPIAAPARSSPQQDAAAGYTDGAPV or APARSSPQQDAAAGYTDGAPV) is predicted from each prepro-hormone. MALDI-FTMS analyses confirmed the presence of all predicted orcokinins, the orcomyotropin-related peptide, and three precursor-related peptides, SSEDMDRLGFGFN, GDYDVYPE (unsulfated) and VYGPRDIANLY, in H. americanus neural tissues. SAE and the longer, unshared peptides were not detected. Similar complements of peptides are predicted from P. clarkii transcripts; the majority of these were detected in its neural tissues with mass spectrometry. Truncated orcokinins not predicted from any precursor were also detected in both species. Consistent with previous studies in the crayfish Orconectes limosus, NFDEIDRSGFGFN increased mid-/hindgut motility in P. clarkii. Surprisingly, the same peptide, although native to H. americanus, did not affect gut motility in this species. Together, our results provide the framework for future investigations of the regulation and physiological function of orcokinins/orcokinin precursor-related peptides in astacideans. © 2008 Elsevier Inc. All rights reserved.
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