20 research outputs found

    Indicator Based Ant Colony Optimization for Multi-objective Knapsack Problem

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    AbstractThe use of metaheuristics to solve multi-objective optimization problems (MOP) is a very active research topic. Ant Colony Optimization (ACO) has received a growing interest in the last years for such problems. Many algorithms have been proposed in the literature to solve different MOP. This paper presents an indicator-based ant colony optimization algorithm called IBACO for the multi-objective knapsack problem (MOKP). The IBACO algorithm proposes a new idea that uses binary quality indicators to guide the search of artificial ants. These indicators were initially used by Zitzler and Künzli in the selection process of their evolutionary algorithm IBEA. In this paper, we use the indicator optimization principle to reinforce the best solutions by rewarding pheromone trails. We carry out a set of experiments on MOKP benchmark instances by applying the two binary indicators: epsilon indicator and hypervolume indicator. The comparison of the proposed algorithm with IBEA, ACO and other state-of-the-art evolutionary algorithms shows that IBACO is significantly better on most instances

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Abstracts from the 3rd International Genomic Medicine Conference (3rd IGMC 2015)

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    Design and implementation of a platform for experimental testing and validation of analog-to-digital converters: static and dynamic parameters

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    This paper presents an implementation of a data acquisition system for analog-to-digital converters (ADCs) using “Laboratory Virtual Instrument Engineering Workbench (LabVIEW)” as software for data analysis. The designed and implemented platform allows interaction with the device under test through means of data acquisition and instrument controls. Developing custom tests in LabVIEW can result in reduced test time, which in turn will help reduce costs in testing. This system was developed for evaluation purposes of ADC's static and dynamic parameters (gain error, offset error, DNL, INL, SNR, SINAD, IMD, etc.) using single and multi-frequency signals. The virtual control and analysis instrument was created in “LabVIEW” environment to control test signals generation and data acquisition. The testing performance of the platform is demonstrated using the classical ADC circuit “ADC0804”. A comparison with experimental results obtained by CANTEST platform from Bordeaux University (France) is also presented to highlight our platform

    Design and implementation of a platform for experimental testing and validation of analog-to-digital converters: static and dynamic parameters

    No full text
    This paper presents an implementation of a data acquisition system for analog-to-digital converters (ADCs) using “Laboratory Virtual Instrument Engineering Workbench (LabVIEW)” as software for data analysis. The designed and implemented platform allows interaction with the device under test through means of data acquisition and instrument controls. Developing custom tests in LabVIEW can result in reduced test time, which in turn will help reduce costs in testing. This system was developed for evaluation purposes of ADC's static and dynamic parameters (gain error, offset error, DNL, INL, SNR, SINAD, IMD, etc.) using single and multi-frequency signals. The virtual control and analysis instrument was created in “LabVIEW” environment to control test signals generation and data acquisition. The testing performance of the platform is demonstrated using the classical ADC circuit “ADC0804”. A comparison with experimental results obtained by CANTEST platform from Bordeaux University (France) is also presented to highlight our platform

    Synthesis and characterization of poly(ester-amide)s from aromatic bisoxazoline precursors

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    International audienceA series of novel aliph. arom. poly(ester-amide)s (PEA) have been synthesized by condensation reaction of arom. bisoxazolines with aliph. dicarboxylic compds. These polymers have a no. av. mol. wt. of 20,000-25,000. Depending of the arom. structure of the bisoxazoline precursor, they are either amorphous or semi-cryst. A good soly. in aprotic solvents was obsd. for all PEA

    Two new β + -thalassemia mutation [ β -56 (G → C); HBBc. −106 G → C ] and [ β −83 (G → A); HBBc. −133 G → A ] described among the Tunisian population

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    International audienceObjectivesDifferent thalassemia mutations have been reported in various ethnic groups and geographical regions in Tunisia. In the present study, we have investigated two rare beta(+)-thalassemia mutations, that have not previously been reported in the Tunisian population [beta -56 (G>C); HBBc. -106 G>C] and [beta -83 (G>A); HBBc. -133 G>A]. MethodsThe whole beta-globin gene was directly sequenced, and haplotype analysis was conducted through a PCR/RFLP method. Results: Two new mutations were identified for the first time in Tunisia. They are located within the promoter region of beta-globin gene at position -56 (G>C) and -83 (G>A). Linkage analysis using beta-globin gene cluster haplotypes showed that these two mutations were associated with Mediterranean beta-haplotype IX [-+-++++] and framework 2 (FW2) [CCTCT]. ConclusionsThe two newly described mutations lead to the beta(+)-thalassemia among Tunisian patients. The haplotype analysis and framework assignment have helped to identify the chromosomal background associated with these mutations, and determine their origin and spread. Am. J. Hum. Biol. 27:716-719, 2015. (c) 2015 Wiley Periodicals, Inc

    GC and GC-MS integrated analyses and in vitro antibacterial, anticholinesterase, anti-tyrosinase, and anti-5-lipoxygenase potential of Inula viscosa root fractionated essential oil

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    Abstract The aim of this study was to characterize the chemical composition of the roots essential oil from Inula viscosa (L.) through its fractionation during extraction, and to evaluate the antibacterial, anticholinesterase, anti-tyrosinase and anti-5-lipoxygenase activities of the isolated oil (REO) and its fractions (R1–R10). The REO and its fractions (R1–R10) were isolated by hydrodistillation of the fresh roots in a Clevenger type apparatus. Fifty-three constituents were identified by GC-FID and GC–MS analyses. The REO was characterized by a high proportion of oxygenated monoterpenes (50.5%), followed by oxygenated sesquiterpenes (37.5%) and sesquiterpene hydrocarbons (7.6%). The major constituents of the REO and all the fractions were (Z)-neryl isovalerate (17.5–29.8%), 1,10-di-epi-cubenol (19.1–27.2%) and 2,5-dimethoxy-p-cymene (5.9–17.7%). The antibacterial activity of REO and its fractions (R1–R10) was tested by using the micro dilution methods against two Gram-positive and four Gram-negative bacteria. The REO and its fractions (R1–R10) showed a strong inhibition of Enterococcus faecalis (MIC = 20.0 μg/mL) and Staphylococcus aureus (MIC = 20.0 μg/mL). Results showed that the fraction R8 exerted the highest anti-tyrosinase activity, with 88.4% of inhibition at 50 μg/mL, and R1 exhibited a significant 5-lipoxygenase inhibitory effect (IC50 = 21.15 ± 0.12 μg/mL)

    Association of Lymphotoxin Alpha Polymorphism with Type 1 Diabetes in a Tunisian Population

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    International audienceWe investigated the association of the lymphotoxin (LT)-alpha gene polymorphism +249A/G with type 1 diabetes. The distribution of genotypes of the LT-alpha +249A/G single nucleotide polymorphism (SNP) was assessed in 115 diabetic patients and 123 normoglycemic control subjects, using PCR-restriction fragment length polymorphism analysis. Among unselected patients, the SNP was significantly associated with increased risk of diabetes (chi(2) = 8.44, p = 0.014) and was found to be more pronounced among female (chi(2) = 8.37, p = 0.02) than male (chi(2) = 6.11, p = 0.047) patients. A significant association was detected between LT-alpha +249A/G and increased risk of diabetes, in particular for young-onset patients (chi(2) = 6.92, p = 0.031). Moreover, we reported significant differences in levels of HbA1c, triglycerides, alanine transaminase, and anti-glutamic acid decarboxylase-65 among alleles. Additional studies with extended patient age groups and different ethnicities are needed to confirm our findings

    Haplotype Map of Sickle Cell Anemia in Tunisia

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    -Globin haplotypes are important to establish the ethnic origin and predict the clinical development of sickle cell disease patients (SCD). To determine the chromosomal background of Tunisian sickle cell patients, in this first study in Tunisia, we have explored four polymorphic regions of -globin cluster on chromosome 11. It is the 5 region of -LCR-HS2 site, the intervening sequence II (IVSII) region of two fetal ( G and A ) genes and the 5 region of -globin gene. The results reveal a high molecular diversity of a microsatellite configuration describing the sequences haplotypes. The linkage disequilibrium analysis showed various haplotype combinations giving 22 "extended haplotypes". These results confirm the utility of the -globin haplotypes for population studies and contribute to knowledge of the Tunisian gene pool, as well as establishing the role of genetic markers in physiopathology of SCD
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