Algorithm for efficient symbolic analysis of large analogue circuits

An algorithm is presented that generates simplified symbolic expressions for the small-signal characteristics of large analogue circuits. The expressions are approximated while they are computed, so that only the most significant terms are generated which remain in the final expression. This principle leads to dramatic savings in CPU time and memory compared to existing techniques, significantly increasing the maximum size of circuits that can be analysed. By taking into account a range for the value of a circuit parameter rather than one single number the generated symbolic expressions are also generally valid

Symbolic analysis of large analog integrated circuits by approximation during expression generation

A novel algorithm is presented that generates approximate symbolic expressions for small-signal characteristics of large analog integrated circuits. The method is based upon the approximation of an expression while it is being computed. The CPU time and memory requirements are reduced drastically with regard to previous approaches, as only those terms are calculated which will remain in the final expression. As a consequence, the maximum circuit size amenable to symbolic analysis has largely increased. The simplification procedure explicitly takes into account variation ranges of the symbolic parameters to avoid inaccuracies of conventional approaches which use a single value. The new approach is also able to take into account mismatches between the symbolic parameters

A Family of matroid intersection algorithms for the computation of approximated symbolic network functions

In recent years, the technique of simplification during generation has turned out to be very promising for the efficient computation of approximate symbolic network functions for large transistor circuits. In this paper it is shown how symbolic network functions can be simplified during their generation with any well-known symbolic network analysis method. The underlying algorithm for the different techniques is always a matroid intersection algorithm. It is shown that the most efficient technique is the two-graph method. An implementation of the simplification during generation technique with the two-graph method illustrates its benefits for the symbolic analysis of large analog circuits

Synthesis for Polynomial Lasso Programs

We present a method for the synthesis of polynomial lasso programs. These programs consist of a program stem, a set of transitions, and an exit condition, all in the form of algebraic assertions (conjunctions of polynomial equalities). Central to this approach is the discovery of non-linear (algebraic) loop invariants. We extend Sankaranarayanan, Sipma, and Manna's template-based approach and prove a completeness criterion. We perform program synthesis by generating a constraint whose solution is a synthesized program together with a loop invariant that proves the program's correctness. This constraint is non-linear and is passed to an SMT solver. Moreover, we can enforce the termination of the synthesized program with the support of test cases.Comment: Paper at VMCAI'14, including appendi

Baja morbilidad en niños operados de nefrectomía con técnica laparoscópica transperitoneal de 3 puertos

ResumenAntecedentesAunque la nefrectomía laparoscópica actualmente se considera el estándar de oro en la cirugía renal del adulto, aún existe controversia de su papel en la población pediátrica. La nefrectomía laparoscópica ha demostrado ser un procedimiento efectivo y seguro comparado con el abordaje abierto.ObjetivoPresentar una serie de casos de pacientes pediátricos con diversas enfermedades renales, tratados con nefrectomía laparoscópica transperitoneal.Materiales y métodosIncluye 22 pacientes pediátricos sometidos a nefrectomía laparoscópica transperitoneal. Todos los casos se realizaron vía laparoscópica con abordaje transperitoneal usando 3 puertos.ResultadosTodos los riñones se removieron satisfactoriamente. El promedio de tiempo operatorio fue de 142min. En 21 de los 22 casos no hubo complicaciones que requirieran conversión cirugía abierta. Se inició dieta y deambulación el mismo día de la cirugía en todos los pacientes y se dio de alta a 20 de los 21 pacientes sin conversión a los 2 días postoperatorios.ConclusionesEn nuestra serie de casos reportamos el abordaje transperitoneal laparoscópico para nefrectomía usando una técnica con 3 puertos que puede ser usada con seguridad en la población pediátrica con los mismos resultados y seguridad que otros procedimientos laparoscópicos. Es una excelente alternativa a la cirugía abierta tradicional y debe ser considerada para disminuir el riesgo quirúrgico.AbstractBackgroundEven though laparoscopic nephrectomy is considered the gold standard in renal surgery in the adult, its role in the pediatric population is still a subject of debate. Laparoscopic nephrectomy has been shown to be a safe and effective procedure, compared with the open approach.AimTo present a case series of pediatric patients with different renal pathologies treated through transperitoneal laparoscopic nephrectomy.Material and methodsTwenty-two pediatric patients that underwent transperitoneal laparoscopic nephrectomy were included in the study. All of the cases underwent the 3-port transperitoneal laparoscopic approach.ResultsAll the kidneys were satisfactorily removed and the mean surgery duration was 142 min. There were no complications requiring conversion to open surgery in 21 of the 22 cases. Oral diet and ambulation were begun the same day of the surgery for all patients. Twenty of the 21 patients that did not require conversion were released on the second postoperative day.ConclusionsWe report herein on the transperitoneal laparoscopic approach for nephrectomy with the 3-port technique. It can be performed in the pediatric population with the same results and safety as other laparoscopic procedures and is an excellent alternative to traditional open surgery. This procedure should be considered for reducing surgical risk

Expression of ABA signalling genes and ABI5 protein levels in imbibed Sorghum bicolor caryopses with contrasting dormancy and at different developmental stages

Background and AimsPre-harvest sprouting susceptibility in grain sorghum (Sorghum bicolor) is related to low seed dormancy and reduced embryo sensitivity to inhibition of germination by abscisic acid (ABA). Intra-specific variability for pre-harvest sprouting might involve differential regulation of ABA signalling genes.MethodsSorghum genes encoding homologues for ABA signalling components from other species (ABI5, ABI4, VP1, ABI1 and PKABA1) were studied at the transcriptional and protein level (ABI5) during grain imbibition for two sorghum lines with contrasting sprouting phenotypes and in response to hormones.Key ResultsTranscript levels of these genes and protein levels of ABI5 were higher in imbibed immature caryopses of the more dormant line. Dormancy loss was related to lower transcript levels of these genes and lower ABI5 protein levels in both genotypes. Exogenous ABA inhibited germination of isolated embryos but failed to prevent ABI5 rapid decrease supporting a role for the seed coat in regulating ABI5 levels.ConclusionsSeveral genes involved in ABA signalling are regulated differently in imbibed caryopses from two sorghum lines with contrasting pre-harvest sprouting response before - but not after - physiological maturity. A role for ABI5 in the expression of dormancy during grain development is discussed.Fil:Rodríguez, M.V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Mendiondo, G.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Maskin, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Gudesblat, G.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Iusem, N.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Homoeologous chromosomal location of the genes encoding thionins in wheat and rye

Thionins are high sulphur basic polypeptides present in the endosperm of Gramineae. In wheat there are three thionins encoded by genes located in the long arms of chromosomes 1A, 1B and 1D. Rye has one thionin encoded by a gene which has been assigned to chromosome 1R after analysis of the Imperial-Chinese Spring rye-wheat disomic addition lines. Commercial varieties and experimental stocks with a 1B/1R substitution carry the thionin from rye ( R) instead of the B thionin from wheat. The R thionin gene is not located in the large chromosomal segment representing most of the short arm of chromosome 1R