RESUMEN
We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}NâηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2 nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}NâηN process and/or a shallow η^{'}-nucleus potential.
Asunto(s)
Lesión Renal Aguda/etiología , Infecciones Neumocócicas/complicaciones , Streptococcus pneumoniae , Lesión Renal Aguda/terapia , Ampicilina/uso terapéutico , Anticoagulantes/uso terapéutico , Transfusión Sanguínea , Ceftazidima/uso terapéutico , Quimioterapia Combinada/uso terapéutico , Nutrición Enteral , Enterocolitis Necrotizante/complicaciones , Enterocolitis Necrotizante/tratamiento farmacológico , Recambio Total de Sangre , Humanos , Recién Nacido , Masculino , Infecciones Neumocócicas/tratamiento farmacológico , Respiración Artificial , Vancomicina/uso terapéuticoRESUMEN
Dark-adapted rods have a suppressive effect on cone response (suppressive rod-cone interaction: SRCI). This phenomenon has been applied to analyze the pathological mechanism of congenital stationary night blindness (CSNB), but the results have been discrepant among the investigators. Alexander et al reported that 2 individuals with CSNB exhibited a normal SRCI, but Arden and Hogg reported an absence of SRCI in 4 cases of CSNB. We evaluated SRCI in complete and incomplete CSNB. SRCI was tested by measuring luminance threshold for flicker detection (685nm, 1.7 degrees in diameter, 20Hz) across the horizontal meridian of the visual field without and with full-field background illumination. In twelve normal subjects, a reduction of the flicker threshold was observed during presentation of the background. Five cases with complete CSNB showed normal SRCI, but in one case we failed to detect SRCI except at one tested locus. Similarly 5 cases of incomplete CSNB showed normal SRCI, but in one case we failed to detect SRCI except at one tested locus. These results may indicate that SRCI is normal in both complete and incomplete CSNB, but in some cases, SRCI is absent because of localized retinal dysfunction.
