46 research outputs found
Studies for the construction of the 100 m telescope
Construction of 100-M telescope for radio astronom
Isoscalar off-shell effects in threshold pion production from pd collisions
We test the presence of pion-nucleon isoscalar off-shell effects in the
reaction around the threshold region. We find that these
effects significantly modify the production cross section and that they may
provide the missing strength needed to reproduce the data at threshold.Comment: 6 pages, REVTeX, twocolumn, including 3 figures (Postscript), uses
psfig, updated and extended versio
Virtual-pion and two-photon production in pp scattering
Two-photon production in pp scattering is proposed as a means of studying
virtual-pion emission. Such a process is complementary to real-pion emission in
pp scattering. The virtual-pion signal is embedded in a background of
double-photon bremsstrahlung. We have developed a model to describe this
background process and show that in certain parts of phase space the
virtual-pion signal gives significant contribution. In addition, through
interference with the two-photon bremsstrahlung background, one can determine
the relative phase of the virtual-pion process
On the Predicted and Observed Color Boundaries of the RR Lyrae Instability Strip as a Function of Metallicity
The purpose of the paper is to predict the temperature at the fundamental
blue edge (FBE) of the instability strip for RR Lyrae (RRL) variables from the
pulsation equation that relates temperature to period, luminosity, and mass.
Modern data for the correlations between period, luminosity, and metallicity at
the FBE for field and cluster RRL are used for the temperature calculation. The
predicted temperatures are changed to B-V colors using an adopted color
transformation. The predicted temperatures at the FBE become hotter as [Fe/H]
changes from 0 to -1.5, and thereafter cooler as the metallicity decreases to
-2.5 and beyond. The temperature range over this interval of metallicity is
log = 0.04, or 640 K at 6900K. The predicted color variation is
at the level of 0.03 mag in B-V. The predictions are compared with the observed
RRL colors at the FBE for both the field and cluster variables, showing general
agreement at the level of 0.02 mag in (B-V), which, however, is the
uncertainty of the reddening corrections.
The focus of the problem is then reversed by fitting a better envelope to the
observed FBE relation between color and metallicity for metallicities smaller
than -1.8 which, when inserted in the pulsation equation, gives a non-linear
calibration ....Comment: 34 pages, 11 figures, 2 tables. To appear in March 2006 A
A unitary model for meson-nucleon scattering
In an effective Lagrangian model employing the K-matrix approximation we
extract nucleon resonance parameters. To this end we analyze simultaneously all
available data for reactions involving the final states , ,
and in the energy range GeV. The background contributions are generated consistently from the
relevant Feynman amplitudes, thus significantly reducing the number of free
parameters.Comment: Revised version. 60 pages, 17 figures. Two figures and a short
discussion (\pi N \to \eta N, K \Lambda amplitudes) added, typos and minor
errors in the citations correcte
Isocalar Roper excitation in the pp --> pp pi0 reaction close to threshold
A new mechanism for the pp --> pp pi0 reaction close to threshold is
suggested coming from the isoscalar excitation of the Roper and its decay into
N(pi pi)S-wave, with one of the pi0 emitted and the other one reabsorbed on the
second nucleon. The mechanism can lead to important interference with other
mechanisms and, together with experiment, serves to exclude large ranges of the
2pi N* decay parameters allowed by the N* partial decay widths.Comment: 11 LaTeX pages, 4 postscript figure
Radioastronomische Messungen an der Sonne mit besonderer Berücksichtigung der Vorgänge während chromosphärischer Eruptionen
Postoperative wound infections. Pathophysiology, risk factors and preventive concepts
Postoperative wound infections are the third most common type of nosocomial infection in German emergency hospitals after pneumonia and urinary infections. They are associated with increased morbidity and mortality, prolonged hospital stay and increased costs. The most important risk factors include the microbiological state of the skin surrounding the incision, delayed or premature prophylaxis with antibiotics, duration of surgery, emergency surgery, poorly controlled diabetes mellitus, malignant disease, smoking and advanced age. Anesthesiological measures to decrease the incidence of wound infections are maintaining normothermia, strict indications for allogenic blood transfusions and timely prophylaxis with antibiotics. Blood glucose concentrations should be kept in the range of 8.3-10 mmol/l (150-180 mg/dl) as lower values are associated with increased complications. Intraoperative and postoperative hyperoxia with 80% O(2) has not been shown to effectively decrease wound infections. The application of local anesthetics into the surgical wound in clinically relevant doses for postoperative analgesia does not impair wound healing