An Application of the Multi-Level Heuristic for the Heterogeneous Fleet Vehicle Routing Problem

The Multi-Level heuristic is used to investigate the heterogeneous fleet vehicle routing problem (HFVRP). The initial solution for the Multi-Level heuristic is obtained by Dijkstra\u27s algorithm based on a cost network constructed by the sweep algorithm and the 2-opt procedure. The proposed algorithm uses a number of local search operators such as swap, 1-0 insertion, 2-opt, and Dijkstra\u27s Algorithm. In addition, in order to improve the search process, a diversification procedure is applied. The proposed algorithm is thentested on the data sets from the literature

3-D Ultrastructure of O. tauri: Electron Cryotomography of an Entire Eukaryotic Cell

The hallmark of eukaryotic cells is their segregation of key biological functions into discrete, membrane-bound organelles. Creating accurate models of their ultrastructural complexity has been difficult in part because of the limited resolution of light microscopy and the artifact-prone nature of conventional electron microscopy. Here we explored the potential of the emerging technology electron cryotomography to produce three-dimensional images of an entire eukaryotic cell in a near-native state. Ostreococcus tauri was chosen as the specimen because as a unicellular picoplankton with just one copy of each organelle, it is the smallest known eukaryote and was therefore likely to yield the highest resolution images. Whole cells were imaged at various stages of the cell cycle, yielding 3-D reconstructions of complete chloroplasts, mitochondria, endoplasmic reticula, Golgi bodies, peroxisomes, microtubules, and putative ribosome distributions in-situ. Surprisingly, the nucleus was seen to open long before mitosis, and while one microtubule (or two in some predivisional cells) was consistently present, no mitotic spindle was ever observed, prompting speculation that a single microtubule might be sufficient to segregate multiple chromosomes

Toxicity Ranking and Toxic Mode of Action Evaluation of Commonly Used Agricultural Adjuvants on the Basis of Bacterial Gene Expression Profiles

The omnipresent group of pesticide adjuvants are often referred to as “inert” ingredients, a rather misleading term since consumers associate this term with “safe”. The upcoming new EU regulation concerning the introduction of plant protection products on the market (EC1107/2009) includes for the first time the demand for information on the possible negative effects of not only the active ingredients but also the used adjuvants. This new regulation requires basic toxicological information that allows decisions on the use/ban or preference of use of available adjuvants. In this study we obtained toxicological relevant information through a multiple endpoint reporter assay for a broad selection of commonly used adjuvants including several solvents (e.g. isophorone) and non-ionic surfactants (e.g. ethoxylated alcohols). The used assay allows the toxicity screening in a mechanistic way, with direct measurement of specific toxicological responses (e.g. oxidative stress, DNA damage, membrane damage and general cell lesions). The results show that the selected solvents are less toxic than the surfactants, suggesting that solvents may have a preference of use, but further research on more compounds is needed to confirm this observation. The gene expression profiles of the selected surfactants reveal that a phenol (ethoxylated tristyrylphenol) and an organosilicone surfactant (ethoxylated trisiloxane) show little or no inductions at EC20 concentrations, making them preferred surfactants for use in different applications. The organosilicone surfactant shows little or no toxicity and good adjuvant properties. However, this study also illustrates possible genotoxicity (induction of the bacterial SOS response) for several surfactants (POEA, AE, tri-EO, EO FA and EO NP) and one solvent (gamma-butyrolactone). Although the number of compounds that were evaluated is rather limited (13), the results show that the used reporter assay is a promising tool to rank commonly used agricultural adjuvants based on toxicity and toxic mode of action data

Bioaccessibility of contaminants of emerging concern in raw and cooked commercial seafood species: insights for food safety risk assessment.

Autoria na publicação: FABIOLA FOGAÇA

Fatness-Associated FTO Gene Variant Increases Mortality Independent of Fatness – in Cohorts of Danish Men

The A-allele of the single nucleotide polymorphism (SNP), rs9939609, in the FTO gene is associated with increased fatness. We hypothesized that the SNP is associated with morbidity and mortality through the effect on fatness.In a population of 362,200 Danish young men, examined for military service between 1943 and 1977, all obese (BMI>or=31.0 kg/m(2)) and a random 1% sample of the others were identified. In 1992-94, at an average age of 46 years, 752 of the obese and 876 of the others were re-examined, including measurements of weight, fat mass, height, and waist circumference, and DNA sampling. Hospitalization and death occurring during the following median 13.5 years were ascertained by linkage to national registers. Cox regression analyses were performed using a dominant effect model (TT vs. TA or AA). In total 205 men died. Mortality was 42% lower (p = 0.001) with the TT genotype than in A-allele carriers. This phenomenon was observed in both the obese and the randomly sampled cohort when analysed separately. Adjustment for fatness covariates attenuated the association only slightly. Exploratory analyses of cause-specific mortality and morbidity prior to death suggested a general protective effect of the TT genotype, whereas there were only weak associations with disease incidence, except for diseases of the nervous system.Independent of fatness, the A-allele of the FTO SNP appears to increase mortality of a magnitude similar to smoking, but without a particular underlying disease pattern barring an increase in the risk of diseases of the nervous system

Ocean current connectivity propelling the secondary spread of a marine invasive comb jelly across western Eurasia

Aim: Invasive species are of increasing global concern. Nevertheless, the mechanisms driving furtherdistribution after the initial establishment of non-native species remain largely unresolved, especiallyin marine systems. Ocean currents can be a major driver governing range occupancy, but this hasnot been accounted for in most invasion ecology studies so far. We investigate how well initialestablishment areas are interconnected to later occupancy regions to test for the potential role ofocean currents driving secondary spread dynamics in order to infer invasion corridors and thesource–sink dynamics of a non-native holoplanktonic biological probe species on a continental scale.Location: Western Eurasia.Time period: 1980s–2016.Major taxa studied: ‘Comb jelly’ Mnemiopsis leidyi.Methods: Based on 12,400 geo-referenced occurrence data, we reconstruct the invasion historyof M. leidyi in western Eurasia. We model ocean currents and calculate their stability to match thetemporal and spatial spread dynamics with large-scale connectivity patterns via ocean currents.Additionally, genetic markers are used to test the predicted connectivity between subpopulations.Results: Ocean currents can explain secondary spread dynamics, matching observed range expansionsand the timing of first occurrence of our holoplanktonic non-native biological probe species,leading to invasion corridors in western Eurasia. In northern Europe, regional extinctions after coldwinters were followed by rapid recolonizations at a speed of up to 2,000 km per season. SourceJASPERS ET AL. | 815areas hosting year-round populations in highly interconnected regions can re-seed genotypes overlarge distances after local extinctions.Main conclusions: Although the release of ballast water from container ships may contribute tothe dispersal of non-native species, our results highlight the importance of ocean currents drivingsecondary spread dynamics. Highly interconnected areas hosting invasive species are crucial forsecondary spread dynamics on a continental scale. Invasion risk assessments should considerlarge-scale connectivity patterns and the potential source regions of non-native marine species