981 research outputs found
The pion-pion scattering amplitude
We obtain reliable scattering amplitudes consistent with
experimental data, both at low and high energies, and fulfilling appropriate
analyticity properties. We do this by first fitting experimental low energy
() phase shifts and inelasticities with expressions
that incorporate analyticity and unitarity. In particular, for the S wave with
isospin~0, we discuss in detail several sets of experimental data. This
provides low energy partial wave amplitudes that summarize the known
experimental information. Then, we impose Regge behaviour as follows from
factorization and experimental data for the imaginary parts of the scattering
amplitudes at higher energy, and check fulfillment of dispersion relations up
to 0.925 GeV. This allows us to improve our fits. The ensuing
scattering amplitudes are then shown to verify dispersion relations up to 1.42
GeV, as well as crossing sum rules and other consistency
conditions. The improved parametrizations therefore provide a reliable
representation of pion-pion amplitudes with which one can test chiral
perturbation theory calculations, pionium decays, or use as input for
CP-violating decays. In this respect, we find
and
.Comment: Version to be published in Phys. Rev. D. Plain TeX file. (minor
changes). 16 figures (some multiple
Manejo integrado de Bromus diandrus. Resultados de tres años de ensayos
En el presente trabajo se aportan los resultados obtenidos
tras tres años de ensayos sobre estrategias de control de Bromus diandrus
en una zona en la que se cultivan principalmente cereales en siembra
directa. Se han rotado, durante los tres años, tres cultivos diferentes
con diversos herbicidas para cada uno, lo cual ha permitido diversificar
tanto las fechas de siembra, de octubre a enero, como los herbicidas utilizados.
El guisante y la cebada, por la siembra tardía, han permitido disminuir
las infestaciones de bromo. Además, la eficacia de los herbicidas
selectivos del guisante es significativamente superior a la de los autorizados
en trigo. El rendimiento del trigo en “rotación” ha sido muy superior
al del trigo en “monocultivo” considerado como estándar. El rendimiento
del guisante ha sido aproximadamente del 55% del trigo en rotación, lo
que garantiza su rentabilidad económica. También el rendimiento de la
cebada, sembrada tras guisante, ha sido muy superior al del trigo.In this paper the results of a
three year experiment for Bromus diandrus management strategies, carried
out in a winter cereal area under no-tillage, are provided. The managements
combine three different crops during three years with various
herbicides for each crop. Sowing dates have been diversified from October
to January, as well as the herbicides. Field pea and barley, by the
fact that are sown late in the season, have reduced Brome infestations.
Moreover, the efficacy of selective herbicides for field pea is significantly
higher than those authorized in wheat. Wheat yield in “rotation” has
been much higher than in “monocrop”. Field pea yield was about 55%
of wheat in rotation, ensuring its profitability. Yield for barley sown after
pea, was also much higher than for wheat
Bromoxynil sensitivity study of a "Papaver rhoeas" L. biotype
“Papaver rhoeas” es la única mala hierba dicotiledónea que presenta resistencia múltiple en España. Se han detectado biotipos resistentes a tribenuron-metil (inhibidor de la acetolactato sintasa) y 2,4-D (auxina sintética). En la zona cerealista del norte de España ha habido problemas en el control de esta mala hierba con mezclas que contenían bromoxinil. En el presente trabajo se ha ensayado, con curvas dosis-respuesta, el efecto de este producto en dos lotes de semillas de un biotipo que no fue controlado en campo por mezclas con bromoxinil en dos años consecutivos. Los lotes B-0313 y B-0314 fueron controlados cuando el bromoxinil se aplicó a la fenología recomendada. Se observó cierto desplazamiento de la curva cuando las plantas de amapola se aplicaron a fenologías más avanzadas.“Papaver rhoeas” is the unique dicot weed that has multiple
resistance in Spain. Resistant biotypes have been detected to tribenuron-
methyl (acetolactate synthase inhibitor) and 2,4-D (synthetic auxin).
In the cereal area of northern Spain there have been problems to
control this weed with mixtures containing bromoxynil. In the present
work we have tested the effect of this product in one biotype that was
not controlled in the field by herbicide mixtures with bromoxynil. The lots B-0313 and B-0314 were controlled with bromoxynil applied at the
recommended phenology. A shift in the curve was observed when corn
poppy plants were applied in more advanced phenologies
The role of antibiotics in the treatment of chronic prostatitis: A consensus statement
Practical guidelines for the diagnosis and treatment of chronic prostatitis are presented. Chronic prostatitis is classified as chronic bacterial prostatitis (culture-positive) and chronic inflammatory prostatitis (culture-negative). If chronic bacterial prostatitis is suspected, based on relevant symptoms or recurrent UTIs, underlying urological conditions should be excluded by the following tests: rectal examination, midstream urine culture and residual urine. The diagnosis should be confirmed by the Meares and Stamey technique. Antibiotic therapy is recommended for acute exacerbations of chronic prostatitis, chronic bacterial prostatitis and chronic inflammatory prostatitis, if there is clinical, bacteriological or supporting immunological evidence of prostate infection. Unless a patient presents with fever, antibiotic treatment should not be initiated immediately except in cases of acute prostatitis or acute episodes in a patient with chronic bacterial prostatitis. The work-up, with the appropriate investigations should be done first, within a reasonable time period which, preferably, should not be longer than 1 week. During this period, nonspecific treatment, such as appropriate analgesia to relieve symptoms, should be given. The minimum duration of antibiotic treatment should be 2-4 weeks. If there is no improvement in symptoms, treatment should be stopped and reconsidered. However, if there is improvement, it should be continued for at least a further 2-4 weeks to achieve clinical cure and, hopefully, eradication of the causative pathogen. Antibiotic treatment should not be given for 6-8 weeks without an appraisal of its effectiveness. Currently used antibiotics are reviewed. Of these, the fluoroquinolones ofloxacin and ciprofloxacin are recommended because of their favourable antibacterial spectrum and pharmacokinetic profile. A number of clinical trials are recommended and a standard study design is proposed to help resolve some outstanding issues
Eficacia de finasterida en el tratamiento de la hematuria asociada a la hiperplasia protática benigna
La hematuria es una complicación de la hiperplasia benigna de próstata (HBP), tanto en su evolución natural como durante el seguimiento post cirugía prostática. En el estudio de Mebust et al., de 3000 pacientes sometidos a prostactectomía por Hiperplasia prostática benigna (HBP), en el 12 % la presencia de hematuria fue la causa de esta indicación quirúrgica (1). Existen escasas referencias de la acción de la finasterida ante dicho síntoma (2-7), aunque los resultados publicados hasta el momento demuestran un efecto terapéutico precoz y estable mientras dura el tratamient
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