On computing fixpoints in well-structured regular model checking, with applications to lossy channel systems

We prove a general finite convergence theorem for "upward-guarded" fixpoint expressions over a well-quasi-ordered set. This has immediate applications in regular model checking of well-structured systems, where a main issue is the eventual convergence of fixpoint computations. In particular, we are able to directly obtain several new decidability results on lossy channel systems.Comment: 16 page

Ecology of Aquatic Plant Myriophyllum Spicatum L. New Record to Kurdistan, Erbil, Iraq

This work deals with the study of aquatic plant Eurasian watermilfoil, Myriophyllum spicatum L. new record to Kurdistan, It is submersed aquatic weed that can easily become excessive in growth and maybe a completely choked small shallow pond. The ecological habitats, distribution, growth characteristic, species description, taxonomical status, economically important and other information, including their control in the aquatic ecosystem, are given in the text. In Kurdistan this plant found in several small and shallow ponds, at the edge of the Greater Zab River behind Kapran village near Gwer sub-district, this area is free from ecological and biological studies.  Ecologically the waters are natural, hard, alkaline, rich in nutrients and Cl-1 ions. And contain a certain amount of heavy metal such as (Mg+², Zn+², Cu+², Fe+², Cr+², Cd) but lead (Pb) was not detected

Dynamics of axialized laser-cooled ions in a Penning trap

We report the experimental characterization of axialization - a method of reducing the magnetron motion of a small number of ions stored in a Penning trap. This is an important step in the investigation of the suitability of Penning traps for quantum information processing. The magnetron motion was coupled to the laser-cooled modified cyclotron motion by the application of a near-resonant oscillating quadrupole potential (the "axialization drive"). Measurement of cooling rates of the radial motions of the ions showed an order-of-magnitude increase in the damping rate of the magnetron motion with the axialization drive applied. The experimental results are in good qualitative agreement with a recent theoretical study. In particular, a classical avoided crossing was observed in the motional frequencies as the axialization drive frequency was swept through the optimum value, proving that axialization is indeed a resonant effect.Comment: 8 pages, 9 figure

Kleene Algebras and Semimodules for Energy Problems

With the purpose of unifying a number of approaches to energy problems found in the literature, we introduce generalized energy automata. These are finite automata whose edges are labeled with energy functions that define how energy levels evolve during transitions. Uncovering a close connection between energy problems and reachability and B\"uchi acceptance for semiring-weighted automata, we show that these generalized energy problems are decidable. We also provide complexity results for important special cases

Towards a Notion of Distributed Time for Petri Nets

We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

Laser cooling in the Penning trap: an analytical model for cooling rates in the presence of an axializing field

Ions stored in Penning traps may have useful applications in the field of quantum information processing. There are, however, difficulties associated with the laser cooling of one of the radial motions of ions in these traps, namely the magnetron motion. The application of a small radio-frequency quadrupolar electric potential resonant with the sum of the two radial motional frequencies has been shown to couple these motions and to lead to more efficient laser cooling. We present an analytical model that enables us to determine laser cooling rates in the presence of such an 'axializing' field. It is found that this field leads to an averaging of the laser cooling rates for the two motions and hence improves the overall laser cooling efficiency. The model also predicts shifts in the motional frequencies due to the axializing field that are in qualitative agreement with those measured in recent experiments. It is possible to determine laser cooling rates experimentally by studying the phase response of the cooled ions to a near resonant excitation field. Using the model developed in this paper, we study the expected phase response when an axializing field is present.Comment: 22 pages, 7 figure

Exploring chemical composition and genetic dissimilarities between maize accessions

The capacity of maize (Zea mays L.) accessions to tolerate drastically extreme conditions in Iraq, contributes to thecharacterization of the genetic resources for germplasm management and the identification of the finest genotypesfor genetic improvement. Therefore, breeding maize program requires knowledge of genetic variation andgenetic structure. A total of 25 maize accessions from three regions (Iraq-Sulaimani, Iraq-Erbil and Iran-Sanandaj)were genotyped by chemical and phytochemical components and simple sequence repeats (SSR) markers to evaluategenetic diversity, population composition and the relationships between genetic and chemical compositiondissimilarities. In terms of proximate and phytochemical parameters, the maize accessions exhibited large significantdisparity, in which oil, phenol contents and 2,2-diphenyl-1-picrylhydrazyl (DPPH) characteristic appeared tobe the most discriminating features of maize accessions. Altogether, 18 SSR markers produced 77 polymorphicalleles across the 25 samples, and the chosen SSR was extremely informative with polymorphic information content(PIC) varied from 0.91 (Bnlg1890) to 0.37 (Umc1630 and Bnlg1189), as well as gene diversity (ranging from0.48 to 0.91, with an average of 0.75) illustrating the broad genetic variability of the accessions investigated.Molecular variance assessment (AMOVA) showed that there was only 21% genetic variation among populations.Pairwise PhiPT distance (0.10 to 0.31) stated high population distinctions among the populations investigated. Inaddition, the accessions from three regions were differentiated into seven clusters by both methods; clusteringand population structure analysis and the accessions are not grouped in term of geographic locations. Both chemicalcomposition and SSR markers differentiated 25 maize accessions. The results of the Mantel test exhibited asignificant positive linkage between chemical components and SSR matrices. The results of this research revealedthat maize accessions have a broad genetic diversity that provides a source of new and unique alleles that arehelpful for maize breeding programs to address the continuing and future significant challenges and determiningcollections of well-known cultivars and disparities between them

Routine delivery of artemisinin-based combination treatment at fixed health facilities reduces malaria prevalence in Tanzania: an observational study

BACKGROUND Artemisinin-based combination therapy (ACT) has been promoted as a means to reduce malaria transmission due to their ability to kill both asexual blood stages of malaria parasites, which sustain infections over long periods and the immature derived sexual stages responsible for infecting mosquitoes and onward transmission. Early studies reported a temporal association between ACT introduction and reduced malaria transmission in a number of ecological settings. However, these reports have come from areas with low to moderate malaria transmission, been confounded by the presence of other interventions or environmental changes that may have reduced malaria transmission, and have not included a comparison group without ACT. This report presents results from the first large-scale observational study to assess the impact of case management with ACT on population-level measures of malaria endemicity in an area with intense transmission where the benefits of effective infection clearance might be compromised by frequent and repeated re-infection. METHODS A pre-post observational study with a non-randomized comparison group was conducted at two sites in Tanzania. Both sites used sulphadoxine-pyrimethamine (SP) monotherapy as a first-line anti-malarial from mid-2001 through 2002. In 2003, the ACT, artesunate (AS) co-administered with SP (AS + SP), was introduced in all fixed health facilities in the intervention site, including both public and registered non-governmental facilities. Population-level prevalence of Plasmodium falciparum asexual parasitaemia and gametocytaemia were assessed using light microscopy from samples collected during representative household surveys in 2001, 2002, 2004, 2005 and 2006. FINDINGS Among 37,309 observations included in the analysis, annual asexual parasitaemia prevalence in persons of all ages ranged from 11% to 28% and gametocytaemia prevalence ranged from <1% to 2% between the two sites and across the five survey years. A multivariable logistic regression model was fitted to adjust for age, socioeconomic status, bed net use and rainfall. In the presence of consistently high coverage and efficacy of SP monotherapy and AS + SP in the comparison and intervention areas, the introduction of ACT in the intervention site was associated with a modest reduction in the adjusted asexual parasitaemia prevalence of 5 percentage-points or 23% (p < 0.0001) relative to the comparison site. Gametocytaemia prevalence did not differ significantly (p = 0.30). INTERPRETATION The introduction of ACT at fixed health facilities only modestly reduced asexual parasitaemia prevalence. ACT is effective for treatment of uncomplicated malaria and should have substantial public health impact on morbidity and mortality, but is unlikely to reduce malaria transmission substantially in much of sub-Saharan Africa where individuals are rapidly re-infected.Financial support for IMPACT-Tz came primarily from CDC, the U.S. Agency for International Development and the Wellcome Trust