Eventration of the diaphragm with gastric volvulus is uncommon. Gastric perforation in these cases is rare and usually associated with acute gastric volvulus with strangulation. We describe a case of diaphragmatic eventration with chronic gastric volvulus with gastric perforation without strangulation in an elderly man.

We examine quark flavour mixing matrices for three and four generations using the recursive parametrization of U(n) and SU(n) matrices developed earlier. After a brief summary of the recursive parametrization, we obtain expressions for the independent rephasing invariants and also the constraints on them that arise from the requirement of mod symmetry of the flavour mixing matrix.

Las matrices de mezcla de sabor de quarks para tres y cuatro generaciones son examinadas usando la parametrización recursiva de las matrices U(n) y SU(n) desarrolladas con anterioridad. Después de un breve resumen de la parametrización recursiva, se obtienen las expresiónes para los invariantes independientes de un cambio de fase y las restricciónes sobre estos que se producen del requerimiento de que la matriz de mezcla de sabor sea modulo simétrica.

Um método espectrofotométrico novo e altamente sensível foi desenvolvido para a determinação do inseticida cipermetrina em níveis de partes por milhão. O método é baseado na hidrólise alcalina de cipermetrina ao íon cianeto, o qual reage posteriormente com iodeto de potássio e leuco cristal violeta. A absorção máxima do corante cristal violeta formado é medida em 595 nm em meio ácido. A lei de Beer é obedecida no intervalo de concentração de 3,0 a 17 µg, em um volume final da solução de 25 mL (0,12-0,68 ppm). A absortividade molar e sensibilidade de Sandell encontradas foram 3,3<FONT FACE=Symbol>´</FONT>10(5) L mol-1 cm-1 e 0,054 µg cm-2, respectivamente. O desvio padrão e desvio padrão relativo foram ± 0,001 e 0,22%, respectivamente. O método é simples, sensível e livre de interferências de outros pesticidas e íons. Outros inseticidas piretróides não interferem no método proposto. O método tem sido aplicado satisfatoriamente para a determinação de cipermetrina em amostras ambientais e biológicas.

A new and highly sensitive spectrophotometric method was developed for the determination of parts per million levels of widely used cypermethrin insecticide. The method is based on alkaline hydrolysis of cypermethrin to cyanide ion, which further reacts with potassium iodide and leuco crystal violet. The absorption maxima of the crystal violet dye formed was measured at 595 nm in acidic medium. Beer's law obeys over the concentration range of 3.0 to 17 µg in a final solution volume of 25 mL (0.12-0.68 ppm). The molar absorptivity and Sandell's sensitivity were found to be 3.3<FONT FACE=Symbol>´</FONT>10(5) L mol-1 cm-1 and 0.054 µg cm-2, respectively. The standard deviation and relative standard deviation were found to be ± 0.001 and 0.22%, respectively. The method is simple, sensitive and free from interferences of other pesticides and diverse ions. Other pyrethroid insecticides do not interfere in the proposed method. The method has been satisfactorily applied to the determination of cypermethrin in environmental and biological samples.

A phenomenological model which has had some success in explaining polarization phenomena and left-right asymmetry in inclusive proton-proton scattering is considered for reactions involving photons. In particular, the reactions (a) gamma + p -> H + X; (b) gamma + p(<IMG SRC="/img/revistas/bjp/v34n3a/a46img01.gif">) <FONT FACE=Symbol>® p</FONT>± + X and (c) p(<IMG SRC="/img/revistas/bjp/v34n3a/a46img01.gif">) -> + p <FONT FACE=Symbol>® g</FONT> + X are considered where gamma = resolved photon and hyperon H = lambda, sigma, xi etc. Predictions for hyperon polarization in (a) and the asymmetry (in (b) and (c)) provide further tests of this particular model. Feasibility of observing (b) at HERA and the effect of the polarization of the sea in the proton in p(<IMG SRC="/img/revistas/bjp/v34n3a/a46img01.gif">) + p <FONT FACE=Symbol>® p</FONT>± + X is briefly discussed.