829,351 research outputs found
P Systems with Anti-Matter
After a short introduction to the area of membrane computing (a branch
of natural computing), we introduce the concept of anti-matter in membrane computing.
First we consider spiking neural P systems with anti-spikes, and then we show the
power of anti-matter in cell-like P systems. As expected, the use of anti-matter objects
and especially of matter/anti-matter annihilation rules, turns out to be rather powerful:
computational completeness of P systems with anti-matter is obtained immediately, even
without using catalysts. Finally, some open problems are formulated, too
(Tissue) P Systems with Anti-Membranes
The concept of a matter object being annihilated when meeting its corresponding
anti-matter object is taken over for membranes as objects and anti-membranes
as the corresponding annihilation counterpart in P systems. Natural numbers can be
represented by the corresponding number of membranes with a speci c label. Computational
completeness in this setting then can be obtained with using only elementary
membrane division rules, without using objects. A similar result can be obtained for tissue
P systems with cell division rules and cell / anti-cell annihilation rules. In both cases,
as derivation modes we may take the standard maximally parallel derivation modes as
well as any of the maximally parallel set derivation modes (non-extendable (multi)sets of
rules, (multi)sets with maximal number of rules, (multi)sets of rules a ecting the maximal
number of objects)
P Systems: from Anti-Matter to Anti-Rules
The concept of a matter object being annihilated when meeting its corresponding
anti-matter object is taken over for rule labels as objects and anti-rule labels
as the corresponding annihilation counterpart in P systems. In the presence of a corresponding
anti-rule object, annihilation of a rule object happens before the rule that the
rule object represents, can be applied. Applying a rule consumes the corresponding rule
object, but may also produce new rule objects as well as anti-rule objects, too. Computational
completeness in this setting then can be obtained in a one-membrane P system
with non-cooperative rules and rule / anti-rule annihilation rules when using one of the
standard maximally parallel derivation modes as well as any of the maximally parallel
set derivation modes (i.e., non-extendable (multi)sets of rules, (multi)sets with maximal
number of rules, (multi)sets of rules a ecting the maximal number of objects). When
using the sequential derivation mode, at least the computational power of partially blind
register machines is obtained
Heavy Hyperon--Antihyperon Production
Based on the experience from the production of anti-Lambda Lambda and
anti-Sigma Sigma pairs at LEAR (experiment PS185) it is suggested to continue
the investigations towards the heavier antihyperon--hyperon pairs anti-Xi Xi
and anti-Omega Omega in view of: (1) the production dynamics of the heavier
antihyperon--hyperon out of the anti-p p annihilation (2) a comparison of the
(3s 3anti-s quark system) anti-Omega Omega to the (3 (anti-s s)) 3 phi meson
production, where both systems have similar masses (3.345 and 3.057,
respectively) and identical valence quark content. A systematic study of the
antihyperon--hyperon production with increasing strangeness content is
interesting for the following reasons: The anti-Omega Omega production is the
creation of two spin 3/2 objects out of the two spin 1/2 anti-p p particles.
Results of the PS185 experiments prove a clear dominance of the spin triplet
anti-s s dissociation. In the Omega anti-Omega the three s-quarks (three anti-s
quarks) are aligned to spin 3/2 each. If the three anti-s s pairs are now all
in spin triplet configurations when created out of the gluonic interaction they
should have spin parity quantum number as 3^- as long as Omega anti-Omega is
created with relative L=0 angular momentum. The comparison of the Omega
anti-Omega baryon pair to the phi phi phi three meson production (where the
three anti-s s quark pairs might not but can be produced without relative
correlation) would provide a unique determination of the intermediate matter
state. Measurements of excitation functions and polarization transfers should
be used to examine these gluon rich anti-p p --> anti-Omega Omega and anti-p p
--> phi phi phi reaction channels. Such experiments should be performed at the
PANDA detector at the FAIR facility of the GSI.Comment: 4 pages, 2 figures, Presented at LEAP05: International Conference on
Low Energy Antiproton Physics, Bonn - Juelich, Germany, May 16-22, 200
Azimuthal correlations of D-mesons in + and +Pb collisions at LHC energies
We study the correlations of D mesons produced in + and +Pb
collisions. These are found to be sensitive to the effects of the cold nuclear
medium and the transverse momentum () regions we are looking into. In
order to put this on a quantitative footing, as a first step we analyse the
azimuthal correlations of D meson-charged hadron(Dh), and then predict the same
for D meson -anti D meson () pairs in + and +Pb
collisions with strong coupling at leading order ()
and next to leading order () which includes space-time
evolution (in both systems), as well cold nuclear matter effects (in +Pb).
This also sets the stage and baseline for the identification and study of
medium modification of azimuthal correlations in relativistic collision of
heavy nuclei at the Large Hadron Collider.Comment: 12 pages, 4 figure
Recent Results from the BRAHMS Experiment
We present recent results obtained by the BRAHMS experiment at the
Relativistic Heavy Ion Collider (RHIC) for the systems of Au + Au and Cu + Cu
at \rootsnn{200} and at 62.4 GeV, and p + p at \rootsnn{200}. Nuclear
modification factors for Au + Au and Cu + Cu collisions are presented. Analysis
of anti-particle to particle ratios as a function of rapidity and collision
energy reveal that particle populations at the chemical freeze-out stage for
heavy-ion reactions at and above SPS energies are controlled by the baryon
chemical potential. From the particle spectra we deduce significant radial
expansion ( 0.75), as expected for systems created with a large
initial energy density. We also measure the elliptic flow parameter
versus rapidity and \ptn. We present rapidity dependent ratios within
for Au + Au and Cu + Cu at \rootsnn{200}. \Raa is found to increase
with decreasing collision energy, decreasing system size, and when going
towards more peripheral collisions. However, \Raa shows only a very weak
dependence on rapidity (for ), both for pions and protons.Comment: 16 pages and 14 figures, proceedings for plenary talk at Quark Matter
2005, Budapest, Hungar
Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model
This study was supported financially
(Grant-Aid Agreement No. MFFRI/07/01) under the Sea Change Strategy with the support of the Marine Institute and the Department of Agriculture, Food and the Marine, funded under the National Development Plan 2007–2013.peer-reviewedThe potential of natural products to prevent obesity have been investigated, with evidence
to suggest that chitosan has anti-obesity effects. The current experiment investigated the
anti-obesity potential of prawn shell derived chitosan on a range of variables relevant to
obesity in a pig model. The two dietary treatment groups included in this 63 day study were:
T1) basal diet and T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group (70 ± 0.90
kg). The parameter categories which were assessed included: performance, nutrient digestibility,
serum leptin concentrations, nutrient transporter and digestive enzyme gene expression
and gut microbial populations. Pigs offered chitosan had reduced feed intake and final
body weight (P< 0.001), lower ileal digestibility of dry matter (DM), gross energy (GE) (P<
0.05) and reduced coefficient of apparent total tract digestibility (CATTD) of gross energy
and nitrogen (P<0.05) when compared to the basal group. Fatty acid binding protein 2
(FABP2) gene expression was down-regulated in pigs offered chitosan (P = 0.05) relative to
the basal diet. Serum leptin concentrations increased (P< 0.05) in animals offered the chitosan
diet compared to pigs offered the basal diet. Fatness traits, back-fat depth (mm), fat
content (kg), were significantly reduced while lean meat (%) was increased (P<0.05) in chitosan
supplemented pigs. Pigs offered chitosan had decreased numbers of Firmicutes in
the colon (P <0.05), and Lactobacillus spp. in both the caecum (P <0.05) and colon (P
<0.001). Bifidobacteria populations were increased in the caecum of animals offered the
chitosan diet (P <0.05). In conclusion, these findings suggest that prawn shell chitosan has
potent anti-obesity/body weight control effects which are mediated through multiple biological
systems in vivo.This study was supported financially
(Grant-Aid Agreement No. MFFRI/07/01) under the Sea Change Strategy with the support of the Marine Institute and the Department of Agriculture, Food and the Marine, funded under the National Development Plan 2007–2013
Event activity-dependence of jet production in p-Pb collisions at TeV measured with semi-inclusive hadron+jet correlations by ALICE
We report measurement of the semi-inclusive distribution of charged-particle
jets recoiling from a high transverse momentum () hadron trigger,
for p-Pb collisions at TeV, in p-Pb events
classified by event activity. This observable has been measured in pp and Pb-Pb
collisions at the LHC, providing a new probe to measure quenching. Jets are
reconstructed from charged particle tracks using anti- with and low IR cutoff of jet constituents ( GeV/).
The complex uncorrelated jet background is corrected by a data-driven approach.
Recoil jet distributions are reported for
GeV/. Events are classified by signal in the ALICE V0A detector, which
measures forward multiplicity, and ZNA, which measures the number of neutrons
at zero degrees. This self-normalized observable does not require scaling of
reference distributions by , thereby avoiding the need for
geometric modeling. We compare the trigger-normalized recoil jet yield for p-Pb
collisions with different event activity to measure the effects of jet
quenching in small systems at the LHC.Comment: Proceedings of the Quark Matter 2017 conference, February 6-11, 201
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