Computing a hyperelliptic integral using arithmetic in the Jacobian of the curve

In this paper, we describe an efficient algorithm for computing an elementary antiderivative of an algebraic function defined on a hyperelliptic curve. Our algorithm combines B. M. Trager's integration algorithm and a technique for computing in the Jacobian of a hyperelliptic curve introduced by D. G. Cantor. Our method has been implemented and successfully compared to Trager's general algorithm.Work partially made at Departement Informatik ETH ZurichUnité de Recherche Associée au CNRS 1586     

Interfacial area and gas-side mass transfer coefficient of a gas—liquid absorption column: pilot-scale comparison of various tray types

The method of gas—liquid absorption with chemical reaction was applied to determine the interfacial area and the gas-side mass transfer coefficient and implemented in a pilot column of diameter 0.45 m. This absorber was equipped successively with different trays of industrial type (bubble-cap, sieve and valve trays), so that a reliable comparison of their respective efficiencies could be made. The influence of weir height was studied especially, and also the effects of gas velocity and liquid load. The experimental results were correlated by means of empirical relations which account for the respective influences of the three parameters and provide a useful basis for extrapolation to industrial absorber design.     

A partition model approach to updating universal scheme interfaces

The updating of relational databases has received extensive attention in the past few years. However, the various methods proposed present two main drawbacks: either the method cannot perform some update because of nondeterminism, or the method is deterministic but leads to counterintuitive results. In this paper, we use partition semantics to study updating in universal scheme interfaces. It is shown that, contrary to other approaches, the main difficulties are due to nondeterminism of deletions. We characterize when a deletion is deterministic or not, and we show how partition semantics allow for choices in certain cases of nondeterminism     

Strategies in frozen donor semen procreation

Data were analysed from 710 couples who had been assessed to determine the effectiveness and the drawbacks of three different methods of insemination using frozen donor semen. Intracervical insemination (ICI) was the first method used when the women had no tubal disorder: 255 pregnancies were achieved in a total of 2558 cycles (10%). Intrauterine insemination (IUI) associated with ovarian stimulation resulted in 152 pregnancies over 966 cycles (16%). In-vitro fertilization (IVF) was proposed after approximately 12 insemination failures using either of the other methods or when the initial gynaecological examination had revealed abnormalities such as tubal occlusions; 48 pregnancies were obtained in 262 cycles (18.3%). The pregnancy rate using ICI was significantly higher when two inseminations were performed per cycle, compared with one insemination per cycle (12.3 versus 7%, P < 0.001). The number of motile spermatozoa per straw was correlated with the pregnancy rate when using ICI, rising from 9% with < 4 x 10(6) motile spermatozoa to 13.8% with 4-8 x 10(6) and 17.2% with > 8 x 10(6). No relationship was found between the number of motile spermatozoa and the pregnancy rate using IUI and IVF. The incidence of primary ovulatory disorder was higher among women whose husbands were oligozoospermic than among those whose husbands were azoospermic (19 versus 9%, P < 0.01), but ovarian stimulation improved the fecundity of subfertile women. The outcome of pregnancies was also analysed for the three methods. From these data, strategic plans have been proposed to maximize the pregnancy rate for women undergoing therapeutic donor insemination with frozen semen.     

State-feedback control of systems with multiplicative noise via linear matrix inequalities

We consider LTI systems perturbed by parametric uncertainties, modeled as white noise disturbances. We show how to maximize, via state-feedback control, the smallest norm of the noise intensity vector producing instability in the mean square sense, using convex optimization over linear matrix inequalities. We also show how to maximize performance robustness, where performance is measured by expected output energy, with either bounded initial conditions and zero inputs (classical LQG cost), or zero initial conditions and deterministic inputs of bounded energy (a generalization of the H_∞ norm).     

Sth1p, a Saccharomyces cerevisiae Snf2p/Swi2p homolog, is an essential ATPase in RSC and differs from Snf/Swi in its interactions with histones and chromatin-associated proteins

The essential Sth1p is the protein most closely related to the conserved Snf2p/Swi2p in Saccharomyces cerevisiae. Sth1p purified from yeast has a DNA-stimulated ATPase activity required for its function in vivo. The finding that Sth1p is a component of a multiprotein complex capable of ATP-dependent remodeling of the structure of chromatin (RSC) in vitro, suggests that it provides RSC with ATP hydrolysis activity. Three sth1 temperature-sensitive mutations map to the highly conserved ATPase/helicase domain and have cell cycle and non-cell cycle phenotypes, suggesting multiple essential roles for Sth1p. The Sth1p bromodomain is required for wild-type function; deletion mutants lacking portions of this region are thermosensitive and arrest with highly elongated buds and 2C DNA content, indicating perturbation of a unique function. The pleiotropic growth defects of sth1-ts mutants imply a requirement for Sth1p in a general cellular process that affects several metabolic pathways. Significantly, an sth1-ts allele is synthetically sick or lethal with previously identified mutations in histones and chromatin assembly genes that suppress snf/swi, suggesting that RSC interacts differently with chromatin than Snf/Swi. These results provide a framework for understanding the ATP-dependent RSC function in modeling chromatin and its connection to the cell cycle.     

Anorectal reconstruction by coloperineal anastomosis and dynamic double graciloplasty after abdomino-perineal resection

The aim of this study was to assess the technical and functional results of total anorectal reconstruction with double dynamic graciloplasty after abdominoperineal resection (APR). PATIENTS AND METHODS: From May 1995 to December 1996. 10 patients (6 males and 4 females), with a mean age of 54 years (range 39-74), underwent anorectal reconstruction for low rectal adenocarcinoma. All patients had preoperative radiotherapy and six had postoperative chemotherapy. The surgical procedure was performed in three stages: 1) APR, coloperineal anastomosis, double graciloplasty and ileostomy; 2) three months later, implantation of stimulator and leads; 3) after a two-months training period, the stoma was closed. RESULTS: There was no postoperative mortality. Early and late morbidity occurred in 5 patients: 2 colonic fistulas, 1 necrosis of colon, 1 ileostomy prolapse, 1 neosphincter stenosis, 1 sepsis of stimulator. No patient had recurrence of the disease (mean follow-up 16 months), but two patients died at 3 and 8 months, respectively from anorexia and pulmonary embolism. Seven patients were available for evaluation (2 fistula, 1 death). Before training, the resting pressure and the squeeze pressure were 30 and 175 cm H2O respectively. At the time of evaluation, the electrical stimulated pressure was 95 cm H2O. Six of these 7 patients were continent (5 with spontaneous defecation, 1 with enemas) and 1 was incontinent. CONCLUSIONS: Anorectal reconstruction with dynamic graciloplasty can be an alternative to permanent colostomy for selected patients after APR. However, there is a high morbidity and the quality of life of the patients must be evaluated.     

Characteristics of aluminum-implanted 6H-SiC samples after different thermal treatments

Multiple energy aluminum (Al) implantations were performed at room temperature in n-type epitaxial 6H-SiC layers, aiming at amorphizing the material from the surface up to a depth inferior to 0.5 μm. Annealings were then carried out in an induction furnace. The goal of this paper is to optimize the furnace geometrical configuration, in order to reduce the surface degradation and improve the crystal reordering. This optimization was established for one-side amorphized wafers, which need restricting annealing parameters, and is therefore supposed to be valid for less crystal damaging implantations. Two types of geometrical parameters were essentially studied: the internal configuration, which tends to increase the silicon partial pressure inside the reactor, and the position of the sample, which has a direct influence on the recrystallization and on the dopant electrical activation. The annealings are compared for the same thermal parameters: the plateau temperature (1700 °C), the annealing duration (30 min), and the heating rate (60 °C s⁻¹). The surface roughness was evaluated by using atomic force microscopy. Two final configurations were retained, leading to satisfactory results with respect to the as-implanted material: (i) Rutherford backscattering spectrometry in channeling geometry revealed a very good recrystallization in both cases, giving a signal level similar to the virgin crystal one; (ii) secondary ion mass spectrometry showed two distinct results depending on the sample position: one position led to some material etching, especially the SiC part which was amorphized by the implantation, and the second position gave rise to the deposition of a crudely monocrystalline SiC layer on the surface of the sample implanted side. This coating was found to prevent from any dopant loss by exodiffusion or material etching. Electrical measurements (four-point probe at 300 K) proved an Al substitutional ratio of 97 and 78% depending on the configuration, giving room temperature sheet resistances of about 2×10⁴ and 4×10⁴ Ω sq.⁻¹, respectively, for 4×10¹⁹ cm⁻³ Al implanted samples.     

Curing of unsaturated polyester resins: Viscosity studies and simulations in pre-gel state

The curing of styrene-unsaturated polyester (UP) resins was studied until gelation. The viscosity and gel points were measured during curing and were correlated with curing temperature, initiator concentration, and accelerator concentration. A gelation model concerning the formation of intra-crosslinked polymer coils, called microgels, was proposed. The model describes the gelation mechanism in four stages: induction, microgel formation, transition, and macro-gelation. The kinetic and gelation parameters of the model were experimentally obtained. The gel points and viscosities in the pre-gel state were simulated by the gelation model for isothermal and nonisothermal curings. Comparisons of the simulation results with experimental data showed good agreement.