316 research outputs found
Deterministic Linear Time Constrained Triangulation using Simplified Earcut
Triangulation algorithms that conform to a set of non-intersecting input segments typically proceed in an incremental fashion, by inserting points first, and then segments. Inserting a segment amounts to: (1) deleting all the triangles it intersects; (2) filling the so generated hole with two polygons that have the wanted segment as shared edge; (3) triangulate each polygon separately. In this paper we prove that these polygons are such that all their convex vertices but two can be used to form triangles in an earcut fashion, without the need to check whether other polygon points are located within each ear. The fact that any simple polygon contains at least three convex vertices guarantees the existence of a valid ear to cut, ensuring convergence. Not only this translates to an optimal deterministic linear time triangulation algorithm, but such algorithm is also trivial to implement. We formally prove the correctness of our approach, also validating it in practical applications and comparing it with prior art
Efficient Nitrogen Recovery from Agro-Energy Effluents for Cyanobacteria Cultivation (Spirulina)
The present study aimed to obtain an efficient liquid nitrogen fertilizer from the by-product of anaerobic digestion for its subsequent use in the production of cyanobacteria (Spirulina). A simple recovery technology was tested based on the stripping and acid absorption, modifying temperature (50 and 70 degrees C) and pH (10 and 12), of the ammonia nitrogen contained in the digestate produced in a large-scale plant treating livestock manure and grass silage. The results demonstrated how, at a relatively low temperature (50 degrees C), using sulfuric and citric acid solution, it is possible to recover nitrogen from a digestate in the form of ammonium sulfate and ammonium citrate with yields of 70% and 72.1% respectively. By carrying out Spirulina growth tests, promising results were obtained under semicontinuous production, with a maximum dry biomass daily productivity of 0.344 g L-1 day(-1) with ammonium sulfate and 0.246 gDW L-1 day(-1) with ammonium citrate. The results showed that nitrogen can be efficiently recovered on site by using the organic acid, digestate and waste heat from anaerobic digestion for Spirulina biomass production
Genetic diversity and introgression by AFLP analisys in Phaseolus vulgaris L.
Phaseolus vulgaris L. is an economically important species whose origin is in the America continent where domestication took place and diverged in Mesoamerican and Andean gene pools.
After Columbus’s voyage common bean was introduced into the Iberian Peninsula from which this species spread into the European countries and around the world. In this study investigate the extent of diversity of European germplasm compared to the American germplasm and to define the level
of introgression between the European Mesoamerican and Andean gene pools are investigated. 68 accessions representative of Mesoamerican and Andean American gene pools and 241 accessions from 24 different countries belonging to an European bean core collection were analysed for three
morphologic quantitative (length, height and width ) and 4 qualitative (shape, lighter colour, darker colour and coat pattern of seed) seed characters and for 4 AFLP primer combinations: E-AGT/MGAC, E-AGT/M-GTA, E-ACC/M-AGA and E-ACC/M-ATG. A total of 138 polymorphic bands were scored among the 309 accessions analysed.
The European and the Mesoamerican gene pools had a number of common and very common AFLP polymorphic bands higher than the American and the Andean gene pools. The European
accessions moreover were used for Structure and cpSSR analysis to identify pure and introgressed lines. These groups were compared for morphological traits and AFLP profiles. Results showed significative differences among diverse groups for morphological traits and for AFLP band frequencies, even though the diversity index were the same (He = 0.23).
Hypothesis of introgression among American and European, Mesoamerican and Andean gene pools are discussed
Nuclear and chloroplast microsatellite diversity in Phaseolus vulgaris L. from Sardinia (Italy).
Studies of the level and the structure of
the genetic diversity of local varieties of Phaseolus
vulgaris are of fundamental importance, both for the
management of genetic resources and to improve our understanding of the pathways of dissemination and
the evolution of this species in Europe. We have here
characterized 73 local bean populations from Sardinia
(Italy) using seed traits and molecular markers
(phaseolins, nuSSRs and cpSSRs). American landraces
and commercial varieties were also included for
comparison. We see that: (a) the Sardinian material is
distinct from the commercial varieties considered; (b)
the variation in the seed traits is high and it mostly
occurs among populations (95%); (c) compared to the
American sample and the commercial varieties, the
Sardinian collection has a low level of diversity; (d)
the majority ([95%) of the Sardinian individuals
belong to the Andean gene pool; (e) the Sardinian
material shows a strong genetic structure, both for
cpSSRs and nuSSRs; (f) the nuSSRs and cpSSRs
concur in differentiating between gene pools, but a
lack of congruence between nuclear and chloroplast
has been observed within gene pools; and (g) there
are three putative hybrids between the Andean and
Mesoamerican gene pools. Despite the relatively low
level of diversity, which is probably due to a strong
founder effect, the Sardinian landraces are worth
being conserved and studied further because of their
distinctiveness and because hybridization within and
between the gene pools could generate variation that
will be useful for breeding
A Robust Implicit Optimal Order Formula for Direct Integration of Second Order Orbital Problems
In this paper, a robust implicit formula of optimal order for direct integration of general second order orbital problems of ordinary differential equations (ODEs) is proposed. This method is considered capable avoiding the computational burden and wastage in computer time in connection with the method of reduction to first order systems. The integration algorithms and analysis of the basic properties are based on the adoption of Taylor’s expansion and Dahlquist stability model test. The resultant integration formula is of order ten and it is zero-stable, consistent, convergent and symmetric. The numerical implementation of the method to orbital and two-body problems demonstrates increased accuracy with the same computational effort on comparison with similar second order formulas. Keywords: Optimal-order, Zero-stability, Convergence, Consistent, IVPs, Predictor-corrector, Error constant, Symmetric
Biological Control Efforts of Water hyacinth (Eichhornia crassipes (Mart.) Solm) on Kainji Lake, Nigeria
Biological control of water hyacinth (Eichhornia crassipes (Mart.) Solm) was monitored on Kainji Lake between 1995 and 1999. The two most important host specific natural enemies of water hyacinth (Neochetina eichhorniae and N. bruchi) were used and impacts of the weevils on water hyacinth were monitored on tri-monthly basis. The manual control initiated by the National Institute for Freshwater Fisheries Research (NIFFR) encouraged the fishermen to physically remove water hyacinth from their shores and open water. The lake hydrology, most especially during the drawdown period when the water volume is reduced tremendously, allows water hyacinth plants to be stranded by the bank of the lake thereby leading to massive destruction of the weed population and consequently the weevils population stability. The floristic composition of macrophyte intimately mixed with the water hyacinth was also monitored during the low and high water regimes. Among the prominent plant species found with water hyacinth included Echinochloa stagnina, Mimosa pigra, Polygonium senegalensis Polygonium lanigarium. Sesbania dalzelli, and Vosia cuspidata were found competing with the much favoured Echinochloa spp which serves as forage to livestock around the lake; However, no incidence of weevil attack was observed on any of the vegetation mixed with water hyacinth. Keywords: Biocontol, Kainji Lake, Water hyacinth, Weevils
Introduction bottleneck and the contribute of Mesoamerican and Andean gene pools to common bean (Phaseolus vulgaris L.) diversity in Europe.
Common bean (Phaseolus vulgaris L., 2n = 2x = 22) is the most important edible food legume for direct human consumption in Europe and in the world as it represents a valuable source of proteins, vitamins, fibres, and minerals. Genetic and archaeological studies have shown that domestication of P. vulgaris was originated and domesticated in the New World and has two major gene pools, the Andean and the Mesoamerican, based on their centers of origin in South and Central America, respectively. After the first voyages of Columbus (1492) common bean was brought to Europe but historical and linguistic sources provide little evidence of the introduction and expansion of common bean in Europe. In common bean a large number of nuclear microsatellite markers (nuSSRs) have been already developed and mapped that show relatively high levels of polymorphism, thus providing an attractive choice for describing population structure. However, to the best of our knowledge, population studies of the European common bean, using nuSSRs, so far have been performed with only a small number of landraces or a small number of samples from a few geographic regions. In the present study, we used thirteen highly polymorphic nuSSRs to assess
the genetic structure and level of diversity of a large collection of European landraces (256
individuals), in comparison with a representative American sample (89 individuals). Moreover, to
obtain a detailed picture and to elucidate the effects of bottleneck of introduction and selection for
adaptation during the expansion of common bean over the whole Europe, we also complemented
the nuSSRs analysis by information provided by a Bayesian analysis implemented in
STRUCTURE. Here, we present and discuss the role that inter-gene pool hybridization have had in
shaping the genetic structure of the European bean landraces. The implication for evolution and the
advantages for common bean breeding are also discussed
A NLP Pipeline for the Automatic Extraction of a Complete Microorganism’s Picture from Microbiological Notes
The Italian “Istituto Superiore di Sanità” (ISS) identifies hospital-acquired infections (HAIs) as the most frequent and serious complications in healthcare. HAIs constitute a real health emergency and, therefore, require decisive action from both local and national health organizations. Information about the causative microorganisms of HAIs is obtained from the results of microbiological cultures of specimens collected from infected body sites, but microorganisms’ names are sometimes reported only in the notes field of the culture reports. The objective of our work was to build a NLP-based pipeline for the automatic information extraction from the notes of microbiological culture reports. We analyzed a sample composed of 499 texts of notes extracted from 1 month of anonymized laboratory referral. First, our system filtered texts in order to remove nonmeaningful sentences. Thereafter, it correctly extracted all the microorganisms’ names according to the expert’s labels and linked them to a set of very important metadata such as the translations into national/international vocabularies and standard definitions. As the major result of our pipeline, the system extracts a complete picture of the microorganism
Tagging the Signatures of Domestication in Common Bean (Phaseolus vulgaris) by Means of Pooled DNA Samples
-Background and Aims: The main aim of this study was to use an amplified fragment length polymorphism (AFLP)-based, large-scale screening of the whole genome of Phaseolus vulgaris to determine the effects of selec- tion on the structure of the genetic diversity in wild and domesticated populations.
-Methods: Using pooled DNA samples, seven each of wild and domesticated populations of P. vulgaris were studied using 2506 AFLP markers (on average, one every 250 kb). About 10% of the markers were also analysed on indi-
-Key Results: The most important outcome is that a large fraction of the genome of the common bean (16 %; P, 0.01) appears to have been subjected to effects of selection during domestication. Markers obtained in indivi-
vidual genotypes and were used to infer allelic frequencies empirically from bulk data. In both data sets, tests were made to determine the departure from neutral expectation for each marker using an FST-based method.
dual genotypes were also mapped and classified according to their proximities to known genes and quantitative trait loci (QTLs) of the domestication syndrome. Most of the markers that were found to be potentially under the effects of selection were located in the proximity of previously mapped genes and QTLs related to the domestication syndrome.
- Conclusions: Overall, the results indicate that in P. vulgaris a large portion of the genome appears to have been subjected to the effects of selection, probably because of linkage to the loci selected during domestication. As most
of the markers that are under the effects of selection are linked to known loci related to the domestication syndrome, it is concluded that population genomics approaches are very efficient in detecting QTLs. A method based on bulk DNA samples is presented that is effective in pre-screening for a large number of markers to determine selection signatures
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