Decidability of the Monadic Shallow Linear First-Order Fragment with Straight Dismatching Constraints

The monadic shallow linear Horn fragment is well-known to be decidable and has many application, e.g., in security protocol analysis, tree automata, or abstraction refinement. It was a long standing open problem how to extend the fragment to the non-Horn case, preserving decidability, that would, e.g., enable to express non-determinism in protocols. We prove decidability of the non-Horn monadic shallow linear fragment via ordered resolution further extended with dismatching constraints and discuss some applications of the new decidable fragment.Comment: 29 pages, long version of CADE-26 pape

Modelling ricochet of a cylinder on water using ALE and SPH methods

The ricochet means the rebound off a surface and is a very important scenario in engineering applications. The specific case of an impact of a solid steel body on a water surface has been chosen for the ricochet example. This solid body hits the water surface with a certain velocity and angle and their dependency on the ricochet behaviour is of interest. This impact scenario can be further developed for more complex impact scenarios, like the ditching of aeroplanes, and has been extensively studied in the past. Due to that fact, it was decided to compare the two numerical analyses with each other; SPH in the internal developed code MCM at Cranfield University with the ALE method in the commercial programme LS-Dyna. The early state of the development was the reason that a 2D model was developed in the 3D solver and therefore verification with another method crucial. Therefore the two simulations were set up and the ricochet behaviour investigated. In contrast to the experimental results, these results demonstrate that independent of the numerical method, both models show an unexpected overproduction of ricochet at higher impact velocities, but agree in their over prediction. The benefits arising out of the collaborative approach of SPH and ALE to describe a problem are presented

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

Flashing annihilation term of a logistic kinetic as a mechanism leading to Pareto distributions

It is shown analytically that the flashing annihilation term of a Verhulst kinetic leads to the power--law distribution in the stationary state. For the frequency of switching slower than twice the free growth rate this provides the quasideterministic source of a Levy noises at the macroscopic level.Comment: 1 fi

Trypanosoma evansi e trypanosoma vivax: biologia, diagnóstico e controle.

Tripanosomoses; Taxonomia; Morfologia; Ciclo vital; Teminologia utiilzada para os tripanosomas baseada no Trypanosoma brucei; Manutenção dos Tripanosomas; Variação molecular em Tripanosomas; Ecologia e sociologia da variação antigênica; Genética de populações de Tripanosomas; Diagnóstico; Caracterização molecular; Métodos de controle; Resistência à drogas; Avaliação do uso do tratamento profilático estratégico ou curativo; Quimioterapia da Tripanosomose por Trypanosoma evansi (tratamento curativo); Quimioterapia da Tripanosomose por Trypanosoma vivax (tratamento curativo); Controle estratégico do Trypanosoma evansi através do uso de drogas tripanocidas; Controle estratégico do Trypanosoma vivax através do uso de drogas tripanocidas; Comparação do Isometamidium e Brometo de Homidium como droga profilática; Mecanismos experimentais de liberação lenta contendo Brometo de Homidium e Isometamidium; Análise econômica; Controle dos vetores; Controle através do uso de inseticidas; Piretroides; Utilização de armadilhas impregnadas com inseticidas

Enforcing Termination of Interprocedural Analysis

Interprocedural analysis by means of partial tabulation of summary functions may not terminate when the same procedure is analyzed for infinitely many abstract calling contexts or when the abstract domain has infinite strictly ascending chains. As a remedy, we present a novel local solver for general abstract equation systems, be they monotonic or not, and prove that this solver fails to terminate only when infinitely many variables are encountered. We clarify in which sense the computed results are sound. Moreover, we show that interprocedural analysis performed by this novel local solver, is guaranteed to terminate for all non-recursive programs --- irrespective of whether the complete lattice is infinite or has infinite strictly ascending or descending chains

Особенности морфологии уролитов жителей города Днепропетровска

Приведены первые результаты исследований морфологии уролитов жителей города Днепропетровска. Предложена типизация уролитов по особенностям их морфологии.Наведено перші результати досліджень морфології уролітов жителів міста Дніпропетровська. Запропонована типізація уролітов за особливостями їх морфології.The first results of studies of morphology nephrolyth residents of Dnipropetrovsk. A typing nephrolyth on the specifics of their morphology.

Dynamics of short- and long-term association between a bacterial plant pathogen and its arthropod vector

The dynamics of association between pathogens and vectors can strongly influence epidemiology. It has been proposed that wilt disease epidemics in cucurbit populations are sustained by persistent colonization of beetle vectors (Acalymma vittatum) by the bacterial phytopathogen Erwinia tracheiphila. We developed a qPCR method to quantify E. tracheiphila in whole beetles and frass and used it to assess pathogen acquisition and retention following variable exposure to infected plants. We found that (i) E. tracheiphila is present in frass in as little as three hours after feeding on infected plants and can be transmitted with no incubation period by vectors given brief exposure to infected plants, but also by persistently colonized vectors several weeks following exposure; (ii) duration of exposure influences rates of long-term colonization; (iii) frass infectivity (assessed via inoculation experiments) reflects bacterial levels in frass samples across time; and (iv) vectors rarely clear E. tracheiphila infections, but suffer no apparent loss of fitness. These results describe a pattern conducive to the effective maintenance of E. tracheiphila within cucurbit populations

Unpaired and spin-singlet paired states of a two-dimensional electron gas in a perpendicular magnetic field

We present a variational study of both unpaired and spin-singlet paired states induced in a two-dimensional electron gas at low density by a perpendicular magnetic field. It is based on an improved circular-cell approximation which leads to a number of closed analytical results. The ground-state energy of the Wigner crystal containing a single electron per cell in the lowest Landau level is obtained as a function of the filling factor $\nu$: the results are in good agreement with those of earlier approaches and predict $\nu_{c} \approx 0.25$ for the upper filling factor at which the solid-liquid transition occurs. A novel localized state of spin-singlet electron pairs is examined and found to be a competitor of the unpaired state for filling factor $\nu >1$. The corresponding phase boundary is quantitatively displayed in the magnetic field-electron density plane.Comment: 19 pages, 8 figures, submitted to Phys. Rev. B on 7th April 2001. to appear in Phys. Rev.