1,574 research outputs found
Possible S-wave Dibaryons in SU(3) Chiral Quark Model
In the framework of the SU(3) chiral quark model, the wave baryon-baryon
bound states are investigated. It is found that according to the symmetry
character of the system and the contributions from chiral fields, there are
three types of bound states. The states of the first type, such as
and are deeply bound
dibaryon with narrow widths. The second type states, ,,
and are also bound states, but with broad widths.
, , and are third type states. They, like {\em d}, are weakly bound
only if the chiral fields can provide attraction between baryons.Comment: Latex files, 1 figur
Directional motion of Gallium-based liquid metal induced by asymmetric chemical surrounding
Interfacial, or surface tension, is a significant topic in chemical education. This paper describes the directional motion of gallium-based liquid metal drops, resulting from a difference of interfacial tension across the drop. This demonstration can engage students in discovering the underlying chemical principles. A mechanism for the drop’s directional motion is proposed to provide insight into this intriguing phenomenon. It appears that unbalanced chemical environments cause different physical or chemical processes to occur on each hemisphere of the drop, such as a pH difference, redox reactions, galvanic replacement, or adsorption. As a result, a difference in the interfacial tension across the drop is generated, providing the driving force that acts on the drop. This demonstration can be used to introduce the fundamental principles in chemical reactions, such as redox activity, electrical double-layer formation, and interfacial tension
N-N Interactions in the Extended Chiral SU(3) Quark Model
The chiral SU(3) quark model is extended to include coupling between vector
chiral field and quarks. By using this model, the phase shifts of NN scattering
for different partial waves are studied. The results are very similar to those
of the chiral SU(3) quark model calculation, in which one gluon exchange (OGE)
plays dominate role in the short range part of the quark-quark interactions.
Only in the case, the one channel phase shifts of the extended chiral
SU(3) quark model are obviously improved.Comment: 15 pages, 6 figure
Possible Dibaryons with Strangeness s=-5
In the framework of , the binding energy of the six quark system with
strangeness s=-5 is systematically investigated under the SU(3) chiral
constituent quark model. The single channel calculation with
spins S=0 and 3 and the coupled and channel
calculation with spins S=1 and 2 are considered, respectively. The results show
following observations: In the spin=0 case, is a bound dibaryon
with the binding energy being . In the S=1 case,
is also a bound dibaryon. Its binding energy is ranged from to . In the S=2 and S=3 cases, no evidence of bound dibaryons
are found. The phase shifts and scattering lengths in the S=0 and S=1 cases are
also given.Comment: 10 pages, late
Global food efficiency of climate change mitigation in agriculture
Concerns exist regarding potential trade-offs between climate change mitigation in agriculture and food security. Against this background, the Global Biosphere Management Model (GLOBIOM) is applied to a range of scenarios of mitigation of emissions from agriculture to assess the implications of climate mitigation for agricultural production, prices and food availability. The " food efficiency of mitigation " (FEM) is introduced as a tool to make statements about how to attain desired levels of agricultural mitigation in the most efficient manner in terms of food security. It is applied to a range of policy scenarios which contrast a climate policy regime with full global collaboration to scenarios of fragmented climate policies that grant exemptions to selected developing country groups. Results indicate increasing marginal costs of abatement in terms of food calories and suggest that agricultural mitigation is most food efficient in a policy regime with global collaboration. Exemptions from this regime cause food efficiency losses
A study of pentaquark state in the chiral SU(3) quark model
The structure of the pentaquark state uudd-sbar is studied in the chiral
SU(3) quark model as well as in the extended chiral SU(3) quark model, in which
the vector meson exchanges are included. Four configurations of JP=1/2- and
four of JP=1/2+ are considered. The results show that the isospin T=0 state is
always the lowest one for both JP=1/2- and JP=1/2+ cases in various models. But
the theoretical value of the lowest one is still about 200-300 MeV higher than
the experimental mass of . It seems that a dynamical calculation should
be done for the further study.Comment: 9 page
Remarks on Hawking radiation as tunneling from the BTZ black holes
Hawking radiation viewed as a semiclassical tunneling process from the event
horizon of the (2 + 1)-dimensional rotating BTZ black hole is carefully
reexamined by taking into account not only the energy conservation but also the
conservation of angular momentum when the effect of the emitted particle's
self-gravitation is incorporated. In contrast to previous analysis of this
issue in the literature, our result obtained here fits well to the
Kraus-Parikh-Wilczek's universal conclusion without any modification to the
Bekenstein-Hawking area-entropy formulae of the BTZ black hole.Comment: 12pages, no figure, use JHEP3.cls. Version better than published one
in JHE
Further study on 5q configuration states in the chiral SU(3) quark model
The structure of the configuration states with strangeness
is further studied in the chiral SU(3) quark model based on our
previous work. We calculate the energies of fifteen low configurations of the
system, four lowest configurations of with
partition , four of with
partition and seven of
with partition . Some modifications are
made in this further study, i.e., the orbital wave function is extended as an
expansion of 4 different size harmonic oscillator forms; three various forms
(quadratic, linear and error function form) of the color confinement potential
are considered; the states with partition are added, which are unnegligible in the case and were
not considered in our previous paper, further the mixing between configurations
and is
also investigated. The results show that the T=0 state is still always the
lowest one for both and states, and
state is always lower than that of .
All of these modifications can only offer several tens to hundred MeV effect,
and the theoretical value of the lowest state is still about 245 MeV higher
than the experimental mass of . It seems to be difficult to get the
calculated mass close to the observed one with the reasonable parameters in the
framework of the chiral SU(3) quark model when the model space is chosen as a
cluster.Comment: 16 page
SNX27 and SORLA interact to reduce amyloidogenic subcellular distribution and processing of amyloid precursor protein
Proteolytic generation of amyloidogenic amyloid {beta} (A{beta}) fragments from the amyloid precursor protein (APP) significantly contributes to Alzheimer's disease (AD). Although amyloidogenic APP proteolysis can be affected by trafficking through genetically associated AD components such as SORLA, how SORLA functionally interacts with other trafficking components is yet unclear. Here, we report that SNX27, an endosomal trafficking/recycling factor and a negative regulator of the {gamma}-secretase complex, binds to the SORLA cytosolic tail to form a ternary complex with APP. SNX27 enhances cell surface SORLA and APP levels in human cell lines and mouse primary neurons, and depletion of SNX27 or SORLA reduces APP endosome-to-cell surface recycling kinetics. SNX27 overexpression enhances the generation of cell surface APP cleavage products such as soluble alpha-APP C-terminal fragment (CTF{alpha}) in a SORLA-dependent manner. SORLA-mediated A{beta} reduction is attenuated by downregulation of SNX27. This indicates that an SNX27/SORLA complex functionally interacts to limit APP distribution to amyloidogenic compartments, forming a non-amyloidogenic shunt to promote APP recycling to the cell surface
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