RESUMEN
The parity-violating (PV) asymmetry of inclusive π- production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasifree photoproduction off the neutron via the Δ0 resonance. In the context of heavy-baryon chiral perturbation theory, this asymmetry is related to a low-energy constant d(Δ)- that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d(Δ)- in a model benchmarked by the large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A(γ)-=-5.2 to +5.2 ppm. The measurement performed in this work leads to A(γ)-=-0.36±1.06±0.37±0.03 ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V(ud)/V(us). The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form factors using PV electron scattering.
RESUMEN
We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q² = 0.22 GeV²/c² and 0.63 GeV²/c² at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory.
RESUMEN
We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of approximately < 10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.
RESUMEN
BACKGROUND/AIMS: Characterising large areas of the body has always been problematic. The aim of this article is to test a method to evaluate the developed surface areas of dermatological lesions from a 3D textured model of the body's envelope. METHOD: We applied the active contour method to isolate the lesions. Then, by means of the 3D model obtained, we calculated the area. This was tested on standards of known areas. RESULTS: For the standards, the standard deviation between the calculated and theoretical surfaces was under 3%. CONCLUSION: The results obtained indicate the feasibility of the method for studying the efficiency of dermatological treatment.
Asunto(s)
Algoritmos , Inteligencia Artificial , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Modelos Biológicos , Reconocimiento de Normas Patrones Automatizadas/métodos , Fotograbar/métodos , Enfermedades de la Piel/patología , Humanos , Rayos Láser , Fantasmas de Imagen , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Índice de Severidad de la EnfermedadRESUMEN
Eleven patients underwent left transthoracic reoperation for recurrence of hiatus hernia after previous surgical treatment. A left thoracic approach was chosen because of three cases of major obesity, three patients with multiple previous laparotomies, three recurrences of para-esophageal hernia, three associated dyskinetic disorders of lower esophagus. Ten patients underwent a Belsey Mark IV procedure with three myotomies of lower esophagus and one pyloroplasty. One patient underwent a Collis-Belsey procedure. Operative mortality was zero. Every patient had been followed up with a mean of 31 months. Ten patients have a good result. One patient had a massive recurrence of gastroesophageal reflux after Belsey Mark IV which led to a duodenal diversion 18 months later. Although the abdominal approach allows easier dissection of lower esophagus and complementary procedures to the lower esophagus. Results are as good as those of the abdominal approach.
Asunto(s)
Reflujo Gastroesofágico/cirugía , Hernia Hiatal/cirugía , Cirugía Torácica/métodos , Adulto , Anciano , Femenino , Estudios de Seguimiento , Reflujo Gastroesofágico/complicaciones , Hernia Hiatal/complicaciones , Humanos , Masculino , Persona de Mediana Edad , Recurrencia , Reoperación , Insuficiencia del TratamientoRESUMEN
Short and long term results of 52 derivative-surgical procedures (43 choledocho-duodenal and 9 hepatico-jejunal with 45 latero-lateral and 7 termino-lateral approaches) were examined. The procedures were performed on patients with benign bilio-digestive conditions: 46 cases of lithiasis, 2 of which were sump syndromes after latero-lateral derivations, and 6 cases of chronic pancreatitis. Several patients were in poor pre-operative condition, which may have influenced postoperative mortality rates (6%). Morbidity was 15 per cent. Four patients (8%) without anastomotic stenosis had infections of the hepatobiliary system within four years of choledochoduodenostomy. In some cases of benign bilio-digestive lesions, derivative surgery is the procedure of choice, being preferable to endoscopic sphincterotomy. In derivative surgery, a termino-lateral approach has better results than a latero-lateral approach. Furthermore, due to the risk of stasis following a choledochoduodenostomy, a hepaticojejunostomy may be preferable.
Asunto(s)
Cálculos Biliares/cirugía , Pancreatitis/cirugía , Anciano , Coledocostomía , Enfermedad Crónica , Femenino , Cálculos Biliares/epidemiología , Conducto Hepático Común/cirugía , Humanos , Yeyunostomía , Masculino , Pancreatitis/epidemiología , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Factores de RiesgoRESUMEN
We report a series of 12 kidneys harvested from 8 brain-dead patients with unstable haemodynamic condition after in situ renal cooling using the double balloon technique. Material and technique are described. The outcome of the renal grafts is known at 3 and 12 months: 92 percent of the renal grafts were functioning at 3 months and 87 percent at 12 months. The mean serum creatinine level of the recipients with functioning graft was 135 mumol/l at 3 months and 113 mumol/l at 12 months. These results suggest that the in situ renal cooling technique makes it possible to obtain kidneys under unstable haemodynamic conditions.
Asunto(s)
Criopreservación/métodos , Riñón , Preservación de Órganos/métodos , Cateterismo/métodos , HumanosRESUMEN
Although chronic pancreatitis microscopically surrounding pancreatic carcinoma is common, cancer developing in chronic pancreatitis has rarely been shown. We present four such cases seen between 1983 and 1988. All were male, mean age 56.7 years, and all had had previous surgery for complications of chronic pancreatitis (two a pancreatectomy, two a bypass). Chronic pancreatitis was caused by alcohol in three cases, and calcification was present in three. The delay between chronic pancreatitis and pancreatic carcinoma was 2 to 10 years, and in all, pancreatic carcinoma was at an advanced state, with post-surgical survival of 1.5 to 6 months. CA 19.9 level was very high in the three cases in which it was measured. That pancreatic carcinoma is more frequent in populations with chronic pancreatitis, occurring later in life than pancreatic carcinoma that has no coexisting chronic pancreatitis (sixth decade vs. fifth), often with intermediate histology, argues for chronic pancreatitis degenerating into pancreatic carcinoma rather than for a common toxic etiology. Pancreatic carcinoma occurs particularly in calcified chronic pancreatitis, and diagnosis is frequently quite late, due to the non-specificity of symptoms vs. chronic pancreatitis. Delay of appearance is variable, and previous surgery and histological examination excludes obvious coexisting pancreatic carcinoma. Aggressive surgery appears justified if needed for chronic pancreatitis, and chronic pancreatitis should be carefully followed, probably by serial CA 19.9 determinations and guided percutaneous fine needle biopsies when elevated, or when new symptoms are present in chronic pancreatitis.