197 research outputs found
Antiflow of kaons in relativistic heavy ion collisions
We compare relativistic transport model calculations to recent data on the
sideward flow of neutral strange K^0_s mesons for Au+Au collisions at 6 AGeV. A
soft nuclear equation of state is found to describe very well the positive
proton flow data measured in the same experiment. In the absence of kaon
potential, the K^0 flow pattern is similar to that of protons. The kaon flow
becomes negative if a repulsive kaon potential determined from the impulse
approximation is introduced. However, this potential underestimates the data
which exhibits larger antiflow. An excellent agreement with the data is
obtained when a relativistic scalar-vector kaon potential, that has stronger
density dependence, is used. We further find that the transverse momentum
dependence of directed and elliptic flow is quite sensitive to the kaon
potential in dense matter.Comment: 5 pages, Revtex, 4 figure
Tag retention, wound healing, and subsequent reproductive history of southern right whales following satellite-tagging
This paper presents data from 48 resightings of 16 southern right whales that
were satellite-tagged on the South African coast in September 2001, up to and
including 2012. Tag performance in terms of number of days with locations received
was significantly higher in males than females, and lowest in cows with calves, and
attributed to behavioral differences leading to variable degrees of antenna damage.
Resightings occurred from 4 to 4,054 d after tagging: tags were retained in all
whales seen within 27 mo, but were apparently shed in all but one individual seen
within 36 mo of tagging. The exception was a whale that still had the tag present
11 yr after tagging. Healing at the tag site occurred gradually and within 5 yr of
tagging (and 2 yr after tag shedding). No significant difference in the subsequent
frequency of calving was detected between 12 tagged and 382 untagged females
photographed contemporaneously, and although statistical power was low, a 21% or
greater reduction in calving rate in tagged females would seem incompatible with
the observations. The death of one female 3 yr after tagging was more likely attributable
to a ship strike on an animal debilitated by a prolapsed uterus.U.S. National Marine Fisheries Service, Office of Naval Research and gifts from donors to the Oregon State University Marine Mammal Program.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-76922016-04-30hb201
Coastal, offshore, and migratory movements of South African right whales revealed by satellite telemetry
In September 2001, 21 satellite-monitored radio tags were deployed on southern right
whales in South African waters, 15 of which transmitted for 25-161 d. Most coastwise
movement on the south coast occurred in a westerly direction with cow-calf pairs
moving slowest. Three whales tagged on the west coast and one tagged on the south
coast moved north into St Helena Bay, a probable feeding ground, where residence
times were 36-100 d. Five animals tracked after leaving the coast maintained a
bearing of 201-220o before branching out over the southeast Atlantic from 37-60o S
and between 13o W and 16o E, travelling 3800-8200 km over the ensuing 53-110 d
before transmissions ceased. Their locations were categorized as migrating or nonmigrating
based on the relative orientation of the track and net speed. An average of
42% of non-migrating locations were between 37-45o S and 53% south of 52o S,
possibly associated with the Sub Tropical Convergence and Antarctic Polar Front
respectively. Whaling data suggest right whales fed largely on copepods at the former
and euphausiids at the latter. If the non-migrating locations represented feeding at
these frontal zones, switching between them would seem to have obvious cost-benefit
implications.P. B. B. acknowledges the support of the
National Research Foundation of South Africa (GUN number 2047517). B. R. M. acknowledges
the support of the National Oceanic and Atmospheric Administration through the
Northeast Consortium, based at the University of New Hampshire (Grant #NA16FL1324),
the U.S. Office of Naval Research, and donors to the Oregon State University Endowed Marine
Mammal Program.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692ab201
Diurnal and seasonal variability in bird counts in a forest fragment in southeastern Brazil
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
Co-occurring morphologically distinct algae support a diverse associated fauna in the intertidal zone of Araçá Bay, Brazil
Kaon properties in (proto)neutron stars
The modification on kaon and antikaon properties of in the interior of
(proto-)neutron stars is investigated using a chiral SU(3) model. The
parameters of the model are fitted to nuclear matter saturation properties,
baryon octet vacuum masses, hyperon optical potentials and low energy a
kaon-nucleon scattering lengths. We study the kaon/antikaon medium modification
and explore the possibility of antikaon condensation in (proto-)neutron star
matter at zero as well as finite temperature/entropy and neutrino content. The
effect of hyperons on kaon and antikaon optical potentials is also investigated
at different stages of the neutron star evolution.Comment: 17 pages including 4 figure
Recognize fish as food in policy discourse and development funding
The international development community is off-track from meeting targets for alleviating global malnutrition. Meanwhile, there is growing consensus across scientific disciplines that fish plays a crucial role in food and nutrition security. However, this ‘fish as food’ perspective has yet to translate into policy and development funding priorities. We argue that the traditional framing of fish as a natural resource emphasizes economic development and biodiversity conservation objectives, whereas situating fish within a food systems perspective can lead to innovative policies and investments that promote nutrition-sensitive and socially equitable capture fisheries and aquaculture. This paper highlights four pillars of research needs and policy directions toward this end. Ultimately, recognizing and working to enhance the role of fish in alleviating hunger and malnutrition can provide an additional long-term development incentive, beyond revenue generation and biodiversity conservation, for governments, international development organizations, and society more broadly to invest in the sustainability of capture fisheries and aquaculture
A search for the decay
We search for the rare flavor-changing neutral-current decay in a data sample of 82 fb collected with the {\sl BABAR}
detector at the PEP-II B-factory. Signal events are selected by examining the
properties of the system recoiling against either a reconstructed hadronic or
semileptonic charged-B decay. Using these two independent samples we obtain a
combined limit of
at the 90% confidence level. In addition, by selecting for pions rather than
kaons, we obtain a limit of using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let
High-reflectivity broadband distributed Bragg reflector lattice matched to ZnTe
We report on the realization of a high quality distributed Bragg reflector
with both high and low refractive index layers lattice matched to ZnTe. Our
structure is grown by molecular beam epitaxy and is based on binary compounds
only. The high refractive index layer is made of ZnTe, while the low index
material is made of a short period triple superlattice containing MgSe, MgTe,
and ZnTe. The high refractive index step of Delta_n=0.5 in the structure
results in a broad stopband and the reflectivity coefficient exceeding 99% for
only 15 Bragg pairs.Comment: 4 pages, 3 figure
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