450 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
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
Recubrimientos comestibles antifúngicos para la preservación de fruta fresca en poscosecha
Las pérdidas de fruta fresca en poscosecha son causadas principalmente por pérdida de peso, alteraciones fisiológicas y podredumbres causadas por hongos filamentosos. Actualmente, estas pérdidas se reducen mediante conservación frigorÃfica y tratamientos poscosecha con fungicidas quÃmicos convencionales y/o ceras sintéticas. Sin embargo, el uso continuado de
tratamientos quÃmicos conlleva importantes problemas como son la generación de residuos quÃmicos y su presencia en la fruta, con los consiguientes riesgos para el consumidor, y la proliferación de cepas fúngicas patogénicas resistentes. Por tanto, deben implementarse comercialmente tratamientos alternativos sostenibles y seguros como parte de estrategias de control integrado no contaminante de enfermedades de poscosecha (CINCEP)
Postharvest Disease Control and Quality Maintenance of Fresh Fruits and Vegetables by Antifungal Edible Coatings
Weight loss, physiological disorders, and postharvest diseases are the main causes of economic losses of fresh fruits and vegetables after harvest. Synthetic waxes, commonly amended with chemical fungicides, are currently often applied before cold storage or commercialization to reduce these losses. However, the continuous use of such agrochemicals is arising important health and environmental issues due to the presence of chemical residues on/in the fruit
On the precision of chiral-dispersive calculations of scattering
We calculate the combination (the Olsson sum rule)
and the scattering lengths and effective ranges , and ,
dispersively (with the Froissart--Gribov representation) using, at
low energy, the phase shifts for scattering obtained by Colangelo,
Gasser and Leutwyler (CGL) from the Roy equations and chiral perturbation
theory, plus experiment and Regge behaviour at high energy, or directly, using
the CGL parameters for s and s. We find mismatch, both among the CGL
phases themselves and with the results obtained from the pion form factor. This
reaches the level of several (2 to 5) standard deviations, and is essentially
independent of the details of the intermediate energy region ( GeV) and, in some cases, of the high energy behaviour assumed. We discuss
possible reasons for this mismatch, in particular in connection with an
alternate set of phase shifts.Comment: Version to appear in Phys. Rev. D. Graphs and sum rule added. Plain
TeX fil
Antifungal hydroxypropyl methylcellulose (HPMC)-lipid composite edible coatings and modified atmosphere packaging (MAP) to reduce postharvest decay and improve storability of ‘Mollar de Elche’ pomegranates
Pomegranate exhibits important postharvest quality losses that limit its storage potential, caused mainly by weight loss, chilling injury and fungal diseases. In this work, we evaluated the effect of novel hydroxypropyl methylcellulose (HPMC) edible coatings (ECs) formulated with three different lipids (beeswax (BW), carnauba wax, and glycerol monostearate), as hydrophobic components, and two different GRAS salts (potassium bicarbonate (PBC) and sodium benzoate (SB)), as antifungal ingredients, to control weight loss and natural fungal decay of ‘Mollar de Elche’ pomegranates during storage at 20◦C. Afterwards, selected antifungal ECs and commercial modified atmosphere packaging (MAP) films were assayed alone or in combination to control natural decay and preserve fruit quality of pomegranates stored at 5◦C for 4 months plus 1 week at 20◦C. Results showed that ECs amended with SB reduced pomegranate latent infections caused by Botrytis cinerea and wound diseases caused by Penicillium spp. Moreover, MAP technologies were confirmed as an efficient mean to preserve freshness, prevent fruit shriveling and rind browning, and reduce fungal decay, thus extending storage life of pomegranates. The combination HPMC-BW-SB + MAP was the most promising treatment as it reduced weight loss and decay, without negatively affecting the fruit physicochemical and sensory quality
Evaluación preliminar de extractos de piel de granada para el control de las podredumbres marrón y amarga en nectarinas
Las podredumbres marrón y amarga, causadas respectivamente por los hongos Monilinia fructicola y Geotrichum candidum, generan importantes pérdidas económicas en la poscosecha de fruta de hueso. Para el control de dichos patógenos, en la actualidad se emplean fungicidas de sÃntesis, como el fludioxonil y el pirimetanil. Sin embargo, debido al perjuicio sobre el medio ambiente y la salud humana que puede ocasionar la acumulación de este tipo de sustancias, se necesitan estrategias de control alternativas no contaminantes, como es la aplicación de extractos naturales vegetales. Numerosos estudios han reportado la actividad antimicrobiana de los extractos de la piel de granada (Punica granatum L.), atribuidos principalmente a su elevado contenido en polifenoles
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