188 research outputs found
Pentaquark searches at FOCUS
We find no evidence for high-energy photoproduction of pentaquarks at 1540
MeV/, 1862 MeV/, or 3099 MeV/ using decay modes ,
, and , respectively.Comment: Proceedings from talk at 2004 DPF Meeting at University of
California, Riversid
On the SigmaN cusp in the pp -> pK+Lambda reaction
Measurements of the reaction at = 2.28 GeV have
been carried out at COSY-TOF. In addition to the FSI and
resonance excitation effects a pronounced narrow structure is observed in the
Dalitz plot and in its projection on the -invariant mass. The
structure appears at the N threshold and is interpreted as
N cusp effect. The observed width of 20 MeV/ is substantially
broader than anticipated from previous inclusive measurements. Angular
distributions of this cusp structure are shown to be dissimilar to those in the
residual channel, but similar to those observed in the
channel
Investigating the Unexpected Behavior for the Release Kinetics of Brilliant Blue Encapsulated into Calcium Alginate Beads
This work is focused on investigating the unexpected behavior for the release kinetics of brilliant blue (BB) encapsulated into calcium alginate beads. By increasing the alginate concentration from 1-3% (w/v), the release of BB over time was found to follow two different behaviors. For the first two hours, the order was 1% > 2% > 3%, after which it was as follow: 1% > 3% > 2%. The unanticipated increase in BB release using 3% (w/v) alginate beads after two hours over that of 2% (w/v) alginate was examined by the swelling and bursting tests. The results were showing clear evidences by data and image the unusual behavior of 3% (w/v) alginate beads at two hours of swelling. This unexpected behavior for the 3% (w/v) alginate beads might be due to the higher osmotic pressure inside the beads. Overall, 2% (w/v) calcium alginate beads were considered to be the optimum formulation showing an excellent carrier for targeting drugs to the intestine, where the swelling of the beads were 60 % in the acidic medium, it was 5000 % in the alkaline medium
EFFECT OF SOME MAJOR ELEMENTS ON GROWTH PERFORMANCE AND BLOOD PARAMETERS IN FISH
he present experiment was conducted to determine the optimal source and level of phosphorus supplementation in commercial feeds with the highest growth rate and the lowest releasing in environmental and protect water quality of Nile Juveniles tilapia (Oreochromis niloticus). Fish were divided into twelve groups (groups) each group was stocked into two aquaria each contains 10 fish. Fish were fed diet contained different levels of phosphorus (0.005, 0.007, 0.009 and 0.011%Kg diet phosphorus) from  three different sources of phosphorus (mono calcium phosphate, mono potassium phosphate and mono sodium phosphate) for a period of 12 weeks. Results showed that average daily gain, specific growth rate, protein efficiency ratio and feed conversation ratio were significantly improved at (p) 1.1% dietary phosphorus level with mono sodium phosphate as the source of phosphorus, mono calcium phosphate represented the highest significant (P<0.05) value of growth and blood parameters (Packed cell volume (PCV), Hemoglobein(Hb) ,red blood cell(RBC) and white blood cell(WBC) in Oreochromis niloticus . Concerning levels of phosphorus the result clearly indicated that the 0.9% phosphorus level recorded the significant (P<0.05) highest growth and blood parameters in Oreochromis niloticus. Body composition analysis showed that the whole body protein and ash content were increased linearly but lipid was decreased (P<0.05) with increasing dietary of phosphorus
Phenomenology of pp->pp eta reaction close to threshold
The recent high statistics measurement of the pp -> pp eta reaction at an
excess energy Q=15.5 MeV has been analysed by means of partial wave
decomposition of the cross section. Guided by the dominance of the final state
1S0 pp interaction (FSI), we keep only terms involving the FSI enhancement
factor. The measured p-p and p-eta effective mass spectra can be well
reproduced by lifting the standard on-shell approximation in the enhancement
factor and by allowing for a linear energy dependence in the leading 3P0->1S0,s
partial wave amplitude. Higher partial waves seem to play only a marginal role
Production of Lambda and Sigma^0 hyperons in proton-proton collisions
This paper reports results on simultaneous measurements of the reaction
channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239,
and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and
differential cross sections are given for both reactions. It is concluded from
the measured total cross sections that the high energy limit of the cross
section ratio is almost reached at an excess energy of only about 200 MeV. From
the differential distributions observed in the overall CMS as well as in the
Jackson and helicity frames, a significant contribution of interfering nucleon
resonances to the \Lambda production mechanism is concluded while resonant
\Sigma^0-production seems to be of lesser importance and takes place only
through specific partial waves of the entrance channel. The data also indicate
that kaon exchange plays a minor role in the case of \Lambda- but an important
role for \Sigma^0-production. Thus the peculiar energy dependence of the
\Lambda-to-\Sigma^0 cross section ratio appears in a new light as its
explanation requires more than mere differences between the p\Lambda and the
p\Sigma^0 final state interaction. The data provide a benchmark for theoretical
models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A
(EPJ A
Salivary PCR detection of Helicobacter pylori DNA in Egyptian patients with dyspepsia
AbstractSeveral methods are available for detecting Helicobacter pylori infection: (1) invasive methods based on gastric biopsies, (2) non invasive methods like Urea Breath Test (UBT), serology and stool antigen tests. Importance of salivary PCR in detection of H. pylori is still questionable. To evaluate the role of salivary PCR technique in detecting H. pylori gastric affection in Egyptian patients with dyspepsia and in differentiating between functional dyspepsia and acid-ulcer syndrome. This study included 60 patients with dyspepsia classified into three groups: (Group 1) patients with gastric H. pylori and ulcers or erosions (n=20), (Group 2) patients with gastric H. pylori and no ulcers or erosions and had functional dyspepsia (n=20), (Group 3) patients without H. pylori and had functional dyspepsia (n=20). All underwent upper gastrointestinal endoscopy with biopsies, rapid urease test and salivary samples for H. pylori PCR. Significant difference between the three groups regarding salivary PCR values. No significant difference between Group 1 and Group 2 but both had significant difference with Group 3, significant difference between gastric H. pylori positive patients (n=40) and negative ones (n=20). Salivary PCR test had sensitivity of 85%, specificity of 70% in diagnosing H. pylori. PCR value of 534000Iu/ml had best sensitivity (75%) and specificity (100%) for diagnosing H. pylori, highly significant positive correlation between H. pylori gastric affection and salivary PCR values. No significant difference between patients with acid ulcer syndrome (n=20) and those with functional dyspepsia (n=40) as regard salivary PCR mean values. Salivary PCR test showed sensitivity of 100%, specificity of 50% in differentiating between patients with acid ulcer syndrome and those with functional dyspepsia. PCR value of 440000 Iu/ml had best sensitivity (100%) and specificity (55%) in differentiating acid ulcer syndrome from functional dyspepsia with non significant. H. pylori salivary PCR may be of value in diagnosing H. pylori gastric affection and is strongly correlated with it but it is of limited value in differentiating between acid ulcer syndrome and functional dyspepsia
Systematic study of the pp -> pp omega reaction
A systematic study of the production of omega-mesons in
proton-proton-collisions was carried out in a kinematically complete experiment
at three excess energies(epsilon= 92, 128, 173MeV). Both protons were detected
using the large-acceptance COSY-TOF spectrometer at an external beam line at
the Cooler Synchrotron COSY at Forschungszentrum J\"ulich. The total cross
section, angular distributions of both omega-mesons and protons were measured
and presented in various reference frames such as the overall CMS, helicity and
Jackson frame. In addition, the orientation of the omega-spin and invariant
mass spectra were determined. We observe omega-production to take place
dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and,
additionally, in Sd at epsilon= 173 MeV. No obvious indication of resonant
omega-production via N^*-resonances was found, as proton angular distributions
are almost isotropic and invariant mass spectra are compatible with phase space
distributions. A dominant role of ^3P_1 and ^1S_0 initial partial waves for
omega-production was concluded from the orientation of the decay plane of the
omega-meson. Although the Jackson angle distributions in the omega-p-Jackson
frame are anisotropic we argue that this is not an indication of a resonance
but rather a kinematical effect reflecting the anisotropy of the omega angular
distribution. The helicity angle distribution in the omega-p-helicity frame
shows an anisotropy which probably reflects effects of the omega angular
momenta in the final state; this observable may be, in addition to the
orientation of the omega decay plane, the most sensitive one to judge the
validity of theoretical descriptions of the production process.Comment: 17 pages, 16 figures, accepted for publication in EPJ
An analysis of the reaction pp --> pp\eta near threshold
It is shown that most of the available data on the reaction,
including the invariant mass distributions in the reaction
recently measured at COSY, can be understood in terms of the partial-wave
amplitudes involving final and states and the meson s-wave.
This finding, together with the fact that results within a meson--exchange
model are especially sensitive to the details of the excitation mechanism of
the resonance, demonstrates the possibility of investigating the
properties of this resonance in collisions. The spin correlation function
is shown to disentangle the - and -wave contributions. It is
also argued that spin correlations may be used to help constrain the
contributions of the amplitudes corresponding to the final Comment: 10 pages, 7 figures, minor revision with one additional figur
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