Tight polynomial bounds for Loop programs in polynomial space

We consider the following problem: given a program, find tight asymptotic bounds on the values of some variables at the end of the computation (or at any given program point) in terms of its input values. We focus on the case of polynomially-bounded variables, and on a weak programming language for which we have recently shown that tight bounds for polynomially-bounded variables are computable. These bounds are sets of multivariate polynomials. While their computability has been settled, the complexity of this program-analysis problem remained open. In this paper, we show the problem to be PSPACE-complete. The main contribution is a new, space-efficient analysis algorithm. This algorithm is obtained in a few steps. First, we develop an algorithm for univariate bounds, a sub-problem which is already PSPACE-hard. Then, a decision procedure for multivariate bounds is achieved by reducing this problem to the univariate case; this reduction is orthogonal to the solution of the univariate problem and uses observations on the geometry of a set of vectors that represent multivariate bounds. Finally, we transform the univariate-bound algorithm to produce multivariate bounds

Carbohydrate composition of mucus released by scleractinian warm- and cold-water reef corals

Mucus, a complex composed primarily of carbohydrates, is released in similar quantities by scleractinian warm- and cold-water reef corals, and can function as an important carrier of organic material from corals to a range of consumers, microbes in particular. However, information about mucus chemical composition is rare for warm-water corals and non-existent for cold-water corals. This study therefore presents comparative carbohydrate composition analyses of mucus released by the dominant and cosmopolitan warm- and cold-water coral genera. Arabinose was the major mucus carbohydrate component for the genus Acropora, but was not found in cold-water coral mucus. Mucus derived from corals of the genus Fungia contained significantly more fucose than the mucus of all other coral genera. However, comparison of mucus carbohydrate composition for the warm- and cold-water corals in the present study and in the literature revealed no significant differences. This indicates use of similar carbohydrate components (with the exception of arabinose) during mucus synthesis by scleractinian corals, largely irrespective of zooxanthellate or azooxanthellate carbon supply mechanisms

Laparoscopic Pectopexy: A Biomechanical Analysis

Introduction Pectopexy, a laparoscopic method for prolapse surgery, showed promising results in recent literature. Further improving this approach by reducing surgical time may decrease complication rates and patient morbidity. Since laparoscopic suturing is a time consuming task, we propose a single suture /mesh ileo-pectineal ligament fixation as opposed to the commonly used continues approach. Methods Evaluation was performed on human non-embalmed, fresh cadaver pelves. A total of 33 trials was performed. Eight female pelves with an average age of 75, were used. This resulted in 16 available ligaments. Recorded parameters were ultimate load, displacement at failure and stiffness. Results The ultimate load for the mesh + simplified single interrupted suture (MIS) group was 35 (+/- 12) N and 48 (+/- 7) N for the mesh + continuous suture (MCS) group. There was no significant difference in the ultimate load between both groups (p>0.05). This was also true for displacement at failure measured at 37 (+/- 12) mm and 36 (+/-5) mm respectively. There was also no significant difference in stiffness and failure modes. Conclusion Given the data above we must conclude that a continuous suture is not necessary in laparoscopic mesh /ileo-pectineal ligament fixation during pectopexy. Ultimate load and displacement at failure results clearly indicate that a single suture is not inferior to a continuous approach. The use of two single sutures may improve ligamental fixation. However, overall stability should not benefit since the surgical mesh remains the limiting factor

Shown is fixation method stiffness for all four subgroups.

<p>ANOVA analysis results are shown as well. Error bars represent standard deviations. M+IS = mesh + interrupted (single) suture, M + CS = mesh + continuous suture, IS = interrupted (single) suture, CS = continuous suture.</p

Shown are representative images of the 4 evaluated groups.

<p>Fig 1.1 shows mesh + continuous suture (MCS). Fig 1.2 shows mesh + a single interrupted suture (MIS). Fig 1.3 shows a continuous suture (CS) and Fig 1.4 shows a single interrupted suture (IS).</p

Shown are maximum loads and displacement at failure for all four subgroups.

<p>ANOVA analysis results are shown as well. Error bars represent standard deviations. M+IS = mesh + interrupted (single) suture, M + CS = mesh + continuous suture, IS = interrupted (single) suture, CS = continuous suture.</p

This table show overall results for all four evaluated groups.

<p>This table show overall results for all four evaluated groups.</p