13,202 research outputs found
Characteristics of Separated Flow Regions Within Altitude Compensating Nozzles Final Report
Characteristics of separated flow regions within altitude compensating nozzle
Vortices in a Bose-Einstein Condensate
We have created vortices in two-component Bose-Einstein condensates. The
vortex state was created through a coherent process involving the spatial and
temporal control of interconversion between the two components. Using an
interference technique, we map the phase of the vortex state to confirm that it
possesses angular momentum. We can create vortices in either of the two
components and have observed differences in the dynamics and stability.Comment: 4 pages with 3 figure
Fitting Neutrino Physics with a U(1)_R Lepton Number
We study neutrino physics in the context of a supersymmetric model where a
continuous R-symmetry is identified with the total Lepton Number and one
sneutrino can thus play the role of the down type Higgs. We show that
R-breaking effects communicated to the visible sector by Anomaly Mediation can
reproduce neutrino masses and mixing solely via radiative contributions,
without requiring any additional degree of freedom. In particular, a relatively
large reactor angle (as recently observed by the Daya Bay collaboration) can be
accommodated in ample regions of the parameter space. On the contrary, if the
R-breaking is communicated to the visible sector by gravitational effects at
the Planck scale, additional particles are necessary to accommodate neutrino
data.Comment: 19 pages, 3 figures; v2: references added, constraints updated,
overall conclusions unchange
First Evidence of Dinosaurian Secondary Cartilage in the Post-Hatching Skull of Hypacrosaurus stebingeri (Dinosauria, Ornithischia)
Bone and calcified cartilage can be fossilized and preserved for hundreds of millions of years. While primary cartilage is fairly well studied in extant and fossilized organisms, nothing is known about secondary cartilage in fossils. In extant birds, secondary cartilage arises after bone formation during embryonic life at articulations, sutures and muscular attachments in order to accommodate mechanical stress. Considering the phylogenetic inclusion of birds within the Dinosauria, we hypothesized a dinosaurian origin for this âavianâ tissue. Therefore, histological thin sectioning was used to investigate secondary chondrogenesis in disarticulated craniofacial elements of several post-hatching specimens of the non-avian dinosaur Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae). Secondary cartilage was found on three membrane bones directly involved with masticatory function: (1) as nodules on the dorso-caudal face of a surangular; and (2) on the bucco-caudal face of a maxilla; and (3) between teeth as islets in the alveolar processes of a dentary. Secondary chondrogenesis at these sites is consistent with the locations of secondary cartilage in extant birds and with the induction of the cartilage by different mechanical factors - stress generated by the articulation of the quadrate, stress of a ligamentous or muscular insertion, and stress of tooth formation. Thus, our study reveals the first evidence of âavianâ secondary cartilage in a non-avian dinosaur. It pushes the origin of this âavianâ tissue deep into dinosaurian ancestry, suggesting the creation of the more appropriate term âdinosaurianâ secondary cartilage
Fruit crops, 1982: a summary of research
Influence of six rootstocks and herbicides on growth, cropping, and fruit quality of Blaxtayman apple trees / David C. Ferree and Robert G. Hill, Jr. -- Tree performance and yield efficiency of several apple cultivars on M9 and M9 interstems / D. C. Ferree -- Chemical induction of lateral shoots on young apple trees / S. C. Myers and D. C. Ferree -- The influence of urea sprays, mulch, and pruning on apple tree decline / G. A. Cahoon and C. W. Donoho, Jr. -- Influence of fireblight and ambrosia beetle on several apple cultivars on M9 and M9 interstems / F. R. Hall, M. A. Ellis, and D. C. Ferree -- A model study of the effect of wind on air sprayer jets / R. D. Fox, D. L. Reichard, and R. D. Brazee -- A comparative study of selected vineyard training and pruning systems for 'Concord' grapevines / G. A. Cahoon -- Effects of selected soil applied herbicides on grapes / Jomo MacDermot and Garth A. Cahoon -- Evaluation of aromatic compounds and virgin females as attractants for rose chafer / Roger N. Williams, Terrence P. McGovern, and Michael Klein -- Botrytis cinerea "gray mold" isolates from strawberry resistant to benlate in Ohio / P. Tanboon-Ek and M. A. Elli
Realistic Standard Model Fermion Mass Relations in Generalized Minimal Supergravity (GmSUGRA)
Grand Unified Theories (GUTs) usually predict wrong Standard Model (SM)
fermion mass relation m_e/m_{\mu} = m_d/m_s toward low energies. To solve this
problem, we consider the Generalized Minimal Supergravity (GmSUGRA) models,
which are GUTs with gravity mediated supersymmetry breaking and higher
dimensional operators. Introducing non-renormalizable terms in the super- and
K\"ahler potentials, we can obtain the correct SM fermion mass relations in the
SU(5) model with GUT Higgs fields in the {\bf 24} and {\bf 75} representations,
and in the SO(10) model. In the latter case the gauge symmetry is broken down
to SU(3)_C X SU(2)_L X SU(2)_R X U(1)_{B-L}, to flipped SU(5)X U(1)_X, or to
SU(3)_C X SU(2)_L X U(1)_1 X U(1)_2. Especially, for the first time we generate
the realistic SM fermion mass relation in GUTs by considering the
high-dimensional operators in the K\"ahler potential.Comment: JHEP style, 29 pages, no figure,references adde
General Gauge and Anomaly Mediated Supersymmetry Breaking in Grand Unified Theories with Vector-Like Particles
In Grand Unified Theories (GUTs) from orbifold and various string
constructions the generic vector-like particles do not need to form complete
SU(5) or SO(10) representations. To realize them concretely, we present
orbifold SU(5) models, orbifold SO(10) models where the gauge symmetry can be
broken down to flipped SU(5) X U(1)_X or Pati-Salam SU(4)_C X SU(2)_L X SU(2)_R
gauge symmetries, and F-theory SU(5) models. Interestingly, these vector-like
particles can be at the TeV-scale so that the lightest CP-even Higgs boson mass
can be lifted, or play the messenger fields in the Gauge Mediated Supersymmetry
Breaking (GMSB). Considering GMSB, ultraviolet insensitive Anomaly Mediated
Supersymmetry Breaking (AMSB), and the deflected AMSB, we study the general
gaugino mass relations and their indices, which are valid from the GUT scale to
the electroweak scale at one loop, in the SU(5) models, the flipped SU(5) X
U(1)_X models, and the Pati-Salam SU(4)_C X SU(2)_L X SU(2)_R models. In the
deflected AMSB, we also define the new indices for the gaugino mass relations,
and calculate them as well. Using these gaugino mass relations and their
indices, we may probe the messenger fields at intermediate scale in the GMSB
and deflected AMSB, determine the supersymmetry breaking mediation mechanisms,
and distinguish the four-dimensional GUTs, orbifold GUTs, and F-theory GUTs.Comment: RevTex4, 45 pages, 15 tables, version to appear in JHE
R.A.Fisher, design theory, and the Indian connection
Design Theory, a branch of mathematics, was born out of the experimental
statistics research of the population geneticist R. A. Fisher and of Indian
mathematical statisticians in the 1930s. The field combines elements of
combinatorics, finite projective geometries, Latin squares, and a variety of
further mathematical structures, brought together in surprising ways. This
essay will present these structures and ideas as well as how the field came
together, in itself an interesting story.Comment: 11 pages, 3 figure
Dynamical response of a Bose-Einstein condensate to a discontinuous change in internal state
A two-photon transition is used to convert an arbitrary fraction of the 87Rb
atoms in a |F=1,m_f=-1> condensate to the |F=2,m_f=1> state. Transferring the
entire population imposes a discontinuous change on the condensate's mean-field
repulsion, which leaves a residual ringing in the condensate width. A
calculation based on Gross-Pitaevskii theory agrees well with the observed
behavior, and from the comparison we obtain the ratio of the intraspecies
scattering lengths for the two states, a_|1,-1> / a_|2,1> = 1.062(12).Comment: 4 pages, 3 figure
Mobility of thorium ions in liquid xenon
We present a measurement of the Th ion mobility in LXe at 163.0 K and
0.9 bar. The result obtained, 0.2400.011 (stat) 0.011 (syst)
cm/(kV-s), is compared with a popular model of ion transport.Comment: 6.5 pages,
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