96 research outputs found
Elective Abdominal Ultrasonography by Surgeons at MNH, Dar-Es-Salaam, Tanzania.
Background: Ultrasound scanning (USS) is an important diagnostic tool in most specialties of surgery. The abdomen is the most commonly scanned region and learning and practicing abdominal USS is the most rewarding. This study was aimed at sharing our experience of elective abdominal ultrasound scanning (USS) done by surgeons at the Department of Surgery, Muhimbili National Hospital (MNH).Methods: This is a retrospective audit of indications and sonographic findings in 1782 elective scannings done over a 42-month period. All scanning was done by surgeons using Aloka SSD 500scanner with a 3.5 MHz probe. Average patient scanning time was 5-10 minutes.Results: The most frequent indications for abdominal ultrasound scanning were abdominal pain (27%), urinary tract symptoms (25%) and abdominal swelling / mass (13%). Overall 47 % of all scanned patients and 58% of those with abdominal pain had normal findings. Of all the patients with abnormal USS findings 42% had abdominal mass. Stone disease was infrequent, seen in 49 (2.7% of all scanned) patients.Conclusion: Pain is the most frequent reason for requesting abdominal ultrasound scanning but it has a low yield of sonographic findings. Scanning for abdominal swelling/mass gave the highest proportion of abnormal findings. USS of a surgical patient done by surgeons expedites diagnostic workup, shortens hospitalization, facilitates biopsy and may help to avoid diagnostic laparotomy
Spectator detection for the measurement of proton neutron interactions at ANKE
A telescope of three silicon detectors has been installed close to the
internal target position of the ANKE spectrometer, which is situated inside the
ultra-high vacuum of the COSY-Juelich light-ion storage ring. The detection and
identification of slow protons and deuterons emerging from a deuterium
cluster-jet target thus becomes feasible. A good measurement of the energy and
angle of such a spectator proton (p_sp) allows one to identify a reaction as
having taken place on the neutron in the target and then to determine the
kinematical variables of the ion-neutron system on an event-by-event basis over
a range of c.m. energies.
The system has been successfully tested under laboratory conditions. By
measuring the spectator proton in the p d to p_sp d pi^0 reaction in
coincidence with a fast deuteron in the ANKE Forward Detector, values of the p
n to d pi^0 total cross-section have been deduced. Further applications of the
telescope include the determination of the luminosity and beam polarisation
which are required for several experiments.Comment: 16 pages, 9 figure
General thoughts to the Kaon pair production in the threshold region
Simple--minded thoughts about the cross sections for the reactions
pp-->ppK+K- and pp-->ppK0K0 are presented, which certainly do not account for
the complex coupled channel problem but rather provide some ideas into the
mutual reaction dynamics.Comment: Talk given at 9th International Workshop on Meson Production,
Properties and Interaction, Cracow, Poland, 9-13 June 2006. 3 pages, 2
figure
Experimental study of the eta-meson interaction with two-nucleons
By means of the COSY-11 detection system, using a stochastically cooled
proton beam of the cooler synchrotron COSY and a hydrogen cluster target, we
have performed a high statistics measurement of the pp --> pp eta reaction at
an excess energy of Q = 15.5 MeV.
The experiment was based on the four-momentum determination of both outgoing
protons. This permits to identify pp --> pp eta events and to derive the
complete kinematical information of the eta-p-p-system allowing for subsequent
investigations of the eta-p interaction.
The observed spectrum of the invariant mass of the proton-proton system
deviates strongly from the phase-space distribution revealing the influence of
the final-state-interaction among the outgoing particles or nontrivial features
of the primary production mechanism.Comment: 6 pages, 4 figures, Talk presented at Meson 2002, 7th International
Workshop on Meson Production, Properties and Interaction, Cracow, Poland,
24-28 May 200
Hadronic interaction of eta and eta-prime mesons with nucleons
Due to their short life-time, flavour-neutral mesons cannot be utilized as
free secondary beams or targets, and therefore a study of their interaction
with nucleons is not possible via direct scattering experiments.
This interaction is, however, accessible via its influence on the energy
dependence - and on the phase space distributions of the cross sections for
reactions in which these mesons are produced.
In case of the p p --> p p eta reaction the experimentally determined
distributions of the differential cross sections close to the production
threshold cannot be described by taking into account the S-wave proton-proton
and proton-eta interaction only. Here we show that the angular distributions
determined at the COSY-11 facility reveal some evidence for P-wave admixture in
the proton-proton subsystem already at an excess energy as low as Q = 15.5 MeV.
We also present that one can estimate the relative strength of the
eta-nucleon and eta-prime-nucleon interactions by comparison of the eta and
eta-prime production yield.Comment: 4 pages, 3 figures, Talk given at 16th International Conference on
Particles and Nuclei (PANIC 02), Osaka, Japan, 30 Sep - 4 Oct 200
Heavy Meson Production at COSY - 11
The COSY-11 collaboration has measured the total cross section for the pp -->
pp eta-prime and pp --> pp eta reactions in the excess energy range from
Q = 1.5 MeV to Q = 23.6 MeV and from Q = 0.5 MeV to Q = 5.4 MeV,
respectively.
Measurements have been performed with the total luminosity of 73 nb^(-1) for
the pp --> pp eta reaction and 1360 nb^(-1) for the pp --> pp eta-prime one.
Recent results are presented and discussed.Comment: Invited talk at 4th International Conference on Physics at Storage
Rings (STORI 99), Bloomington, Indiana, USA, September 12-16, 199
Associated strangeness production in pp collisions near threshold
Motivated by the ongoing discussion concerning the nature of the scalar
resonances f0(980) and a0(980), the COSY-11 collaboration has taken exclusive
data on the pp->ppK+K- reaction near the production threshold. A first total
cross section sigma=(1.80+-0.27+0.28-0.35)nb for the excess energy Q=17 MeV has
been determined. In contrary to the eta, omega and eta' single meson production
studies which clearly show the strong pp final state interaction (FSI), the
cross section values obtained at COSY-11 and DISTO can be both described by a
fit with a four-body phase space including the proton-proton final state
interaction as well as with one-meson exchange calculations neglecting FSI
effects. Therefore, one might think about a compensation of the strong pp
interaction through a pK- FSI effect or an additional degree of freedom caused
by the four-body final state. In the latter case, strong FSI effects can be
expected at Q-values very close to the K+K- production threshold. Such a
motivation triggered -- in combination with the investigation of the
kaon-Antikaon interaction being relevant to the structure of the f0(980) --
further measurements at the excess energies Q=10 and Q=28 MeV at COSY-11.Comment: 5 pages, 4 figures, Presented at X. International Conference On
Hadron Spectroscopy (Hadron 2003), Aschaffenburg, Germany, 31 Aug - 6 Sep
200
Analysing power A(y) in the reaction p(pol.)p --> pp eta near threshold
A first measurement of the analysing power in the reaction p(pol)p --> pp eta
near the production threshold has been performed at the internal facility
COSY-11 at the COoler SYnchrotron COSY.Comment: 4 pages, 2 figures, Presented at Meson 2002: 7th International
Workshop on Production, Properties and Interaction of Mesons, Cracow, Poland,
24-28 May 200
Dynamics of the near threshold eta meson production in proton-proton interaction
We present the results of measurements of the analysing power for the p(pol)p
--> pp eta reaction at the excess energies of Q=10 and 36 MeV, and interpret
these results within the framework of the meson exchange models. The determined
values of the analysing power at both excess energies are consistent with zero
implying that the eta meson is produced predominantly in s-wave.Comment: 3 pages, 3 figures, Presented at the Workshop on the physics of
excited nucleons (NSTAR 2007), 5-8 September 2007, Bonn, German
First close-to-threshold measurement of the analyzing power Ay in the reaction p(pol)p -> pp eta
At the internal facility COSY-11 a first measurement of the reaction p(pol)p
-> pp eta near the production threshold has been performed. Results for the
analysing power will be presented and a comparison with one meson exchange
models will be discussed.Comment: 3 pages, 3 figures, Presented at Conference on Quarks and Nuclear
Physics (QNP 2002), Julich, Germany, 9-14 Jun 200
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