2,982 research outputs found
A description of the f2(1270), rho3(1690), f4(2050), rho5(2350) and f6(2510) resonances as multi-rho(770) states
In a previous work regarding the interaction of two resonances,
the () resonance was obtained dynamically as a
two- molecule with a very strong binding energy, 135~MeV per
particle. In the present work we use the interaction in spin 2 and
isospin 0 channel to show that the resonances (),
(), () and ()
are basically molecules of increasing number of particles. We use
the fixed center approximation of the Faddeev equations to write the multi-body
interaction in terms of the two-body scattering amplitudes. We find the masses
of the states very close to the experimental values and we get an increasing
value of the binding energy per as the number of mesons is
increased.Comment: 17 pages, 6 figure
Recoverin Regulates Light-dependent Phosphodiesterase Activity in Retinal Rods
The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin
Recent developments in chiral dynamics of hadrons and hadrons in nuclei
In this talk I present recent developments in the field of hadronic physics
and hadrons in the nuclear medium. I review the unitary chiral approach to
meson baryon interaction and address the topics of the two dynamically
generated resonances, with experiments testing it, the
and resonances, plus the ,
and in the nuclear medium.Comment: 9 pages, 8 figures, Talk at YKIS06 Kyoto Symposium, Kyoto, december
200
Selected topics on Hadrons in Nuclei
In this talk we report on selected topics on hadrons in nuclei. The first
topic is the renormalization of the width of the in a nuclear
medium. This is followed by a short update of the situation of the in
the medium. The investigation of the properties of in the nuclear
medium from the study of the reaction is also addressed, as
well as properties of X,Y,Z charmed and hidden charm resonances in a nuclear
medium. Finally we address the novel issue of multimeson states.Comment: Talk at the International Nuclear Physics Conference, Vancouver, July
201
Chiral dynamics of hadrons in nuclei
In this talk I report on selected topics of hadron modification in the
nuclear medium using the chiral unitary approach to describe the dynamics of
the problems. I shall mention how antikaons, , and are modified in
the medium and will report upon different experiments done or planned to
measure the width in the medium.Comment: 10 pgs, 3 figs. Invited talk in the Workshop on in Medium Hadron
Physics, Giessen, Nov 200
Recent Developments in Chiral Unitary Dynamics of Resonances
In this talk I summarize recent findings made on the description of axial
vector mesons as dynamically generated states from the interaction of
peseudoscalar mesons and vector mesons, dedicating some attention to the two
states. Then I review the generation of open and hidden charm
scalar and axial states. Finally, I present recent results showing that the low
lying baryon resonances for S=-1 can be obtained as bound states or
resonances of two mesons and one baryon in coupled channels dynamics.Comment: Talk at the International Conference on Hadron Physics, Troia07,
Canakkale, Turkey, Sep. 2007 and at the Chiral Symmetry in Hadron and Nuclear
Physics Workshop, Chiral07, Osaka, November 200
The Upper Oligocene of Montgat (Catalan Coastal Ranges, Spain): New age constrains to the western Mediterranean Basin opening
The Oligocene deposits of Montgat are integrated in a small outcrop made up of Cenozoic and Mesozoic rocks located in the Garraf-Montnegre horst, close to the major Barcelona fault. The Oligocene of Montgat consists of detrital sediments of continental origin mainly deposited in alluvial fan environments; these deposits are folded and affected by thrusts and strike-slip faults. They can be divided in two lithostratigraphic units separated by a minor southwest-directed thrust: (i) the Turó de Montgat Unit composed of litharenites and lithorudites with high contents of quartz, feldspar, plutonic and limestone rock fragments; and (ii) the Pla de la Concòrdia Unit composed of calcilitharenites and calcilithorudites with high contents of dolosparite and dolomicrite rock fragments. The petrological composition of both units indicates that sediments were derived from the erosion of Triassic (Buntsandstein, Muschelkalk and Keuper facies), Jurassic and Lower Cretaceous rocks (Barremian to Aptian in age). Stratigraphic and petrological data suggest that these units correspond to two coalescent alluvial fans with a source area located northwestwards in the adjoining Collserola and Montnegre inner areas. Micromammal fossils (Archaeomys sp.) found in a mudstone layer of the Pla de la Concòrdia Unit assign a Chattian age (Late Oligocene) to the studied materials. Thus, the Montgat deposits are the youngest dated deposits affected by the contractional deformation that led to the development of the Catalan Intraplate Chain. Taking into account that the oldest syn-rift deposits in the Catalan Coastal Ranges are Aquitanian in age, this allows to precise that the change from a compressive to an extensional regime in this area took place during latest Oligocene-earliest Aquitanian times. This age indicates that the onset of crustal extension related to the opening of the western Mediterranean Basin started in southern France during latest Eocene-early Oligocene and propagated southwestward, affecting the Catalan Coastal Ranges and the northeastern part of the Valencia trough during the latest Chattian-earliest Aquitanian times
Interface optical phonons in spheroidal dots: Raman selection rules
The contribution of interface phonons to the first order Raman scattering in
nanocrystals with non spherical geometry is analyzed. Interface optical phonons
in the spheroidal geometry are discussed and the corresponding Frohlich-like
electron-phonon interaction is reported in the framework of the dielectric
continuum approach. It is shown that the interface phonon modes are strongly
dependent on the nanocrystal geometry, particularly on the ellipsoid's
semi-axis ratio. The new Raman selection rules have revealed that solely
interface phonon modes with even angular momentum are allowed to contribute to
the first order phonon-assisted scattering of light. On this basis we are able
to give an explanation for the observed low frequency shoulders present in the
Raman cross-section of several II-VI semiconductor nanostructures.Comment: 8 pages, 2 figure
The effect of a high monounsaturated fat diet on body weight, backfat and loin muscle growth in high and medium-lean pig genotypes
The objective of this study was to evaluate whether the use of a diet rich in oleic acid could have an effect on daily
weight gain, backfat and loin muscle (Longissimus thoracis) depth. One hundred and ninety-two barrows and gilts,
from two genotypes were fed a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic
acid (HO with 43% C18:1, Greedy-Grass OLIVA®). The pigs were housed in 16 pens in groups of 12 according to their
sex, diet and genotype. From 75 days of age every three weeks, the pigs were weighed and the backfat and loin muscle
depth were ultrasonically recorded (PIGLOG®). The inclusion of the dietary fat had no significant effect on the growth
variables nor on the backfat and loin muscle depth measurements taken. However, the barrows resulted in higher live
weight and backfat compared to the gilts at the end of the trial. Conversely, the gilts showed higher loin depth. Moreover,
York-sired pigs were heavier than Pietrain-sired pigs during the whole trial and showed higher backfat at the last two
measurements. Pietrain-sired pigs had higher loin muscle depth at the last measurements. The results of the present
study suggest that the addition of a dietary fat into diets aiming at modifying the meat fatty acid profile has no detrimental effects on performance variables, or on backfat and loin muscle growth and thus, no negative economic impact
for producers.The study was funded by the Spanish Government within the CDTI program (IDI 2004-683). Many thanks for the technical support of IRTA and UPB España, S.A. technicians. The authors would specially like to acknowledge the contribution of Mr. Rafa Roca, who unfortunately passed away during the final writing of this paper.info:eu-repo/semantics/publishedVersio
Axial Resonances in the Open and Hidden Charm Sectors
A SU(4) flavor symmetrical Lagrangian is constructed for the interaction of
the pseudo-scalar mesons with the vector mesons. SU(4) symmetry is broken to
SU(3) by suppression of terms in the Lagrangian where the interaction should be
driven by charmed mesons. Chiral symmetry can be restored by setting this new
SU(4) symmetry breaking parameters to zero. Unitarization in coupled channels
leads to the dynamical generation of resonances. Many known axial resonances
can be identified including the new controversial X(3872) and the structure
found recently by Belle around 3875 MeV in the hidden charm sector. Also new
resonances are predicted, some of them with exotic quantum numbers.Comment: Final published versio
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