Production and fate of the G ring arc particles due to Aegaeon (Saturn LIII)

The G ring arc hosts the smallest satellite of Saturn, Aegaeon, observed with a set of images sent by Cassini spacecraft. Along with Aegaeon, the arc particles are trapped in a 7:6 corotation eccentric resonance with the satellite Mimas. Due to this resonance, both Aegaeon and the arc material are confined to within sixty degrees of corotating longitudes. The arc particles are dust grains which can have their orbital motions severely disturbed by the solar radiation force. Our numerical simulations showed that Aegaeon is responsible for depleting the arc dust population by removing them through collisions. The solar radiation force hastens these collisions by removing most of the 10$~\mu$m sized grains in less than 40 years. Some debris released from Aegaeon's surface by meteoroid impacts can populate the arc. However, it would take 30,000 years for Aegaeon to supply the observed amount of arc material, and so it is unlikely that Aegaeon alone is the source of dust in the arc

Use of by-products rich in carbon and nitrogen as a nutrient source to produce Bacillus thuringiensis (Berliner) -based biopesticide.

The amount and sources of carbon and nitrogen used to produce Bacillus thuringiensis(Berliner)-based biopesticide may in fluence the quality of the final product. The objective of this research was to test different levels of carbon and nitrogen: medium 1 - 1.5% maize glucose + 0.5% soy flour, medium 2 - 3.0% maize glucose + 1.0% soy flour, medium 3 - 1.0% maize glucose + 3.0% soy flour and medium 4 - Luria Bertani (LB) + salts (FeSO4, ZnSO4, MnSO4, MgSO4). The seed culture was produced in LB medium plus salt, under agitation (200 rpm) for 18h at 30oC. The strain 344 of Bt was used (B. thuringiensis var tolworthi ? belonging to the Embrapa ?s Bt Bank). The pH was measured at regular intervals. and After culturing for 96h, the pH of the four tested media was basified (6.91 and 8.15), the number of spores yielded 4.39 x 109 spores/ml in medium 3, where the amount of protein is high. The dry biomass weight accumulated in media 3 was 39.3 g/l. Mortality of 2-day-old larvae Spodoptera frugiperda (J.E. Smith) was 100% when using Bt produced in media 3 and 4. CL50 for medium 3 was 8.4 x 106 spores/ml. All tested media were satisfactory to Bt growth, and medium 3 wass the most promising to be used on a large scale Bt-based biopesticide production. A quantidade de carbono e nitrogênio usados para produzir biopesticidas à base de Bacillus thuringiensis (Berliner) pode influenciar a qualidade final do produto. O objetivo deste trabalho foi testar meios com diferentes níveis de carbono e nitrogênio: meio 1 - glicose de milho a 1.5% + farinha de soja a 0,5%, meio 2 - glicose de milho a 3,0% + farinha de soja a 1,0%, meio 3 - glicose de milho a 1,0% + farinha de soja a 3,0% e meio 4 - Luria Bertani (LB) + sais (FeSO4, ZnSO4, MnSO4 e MgSO4). O inóculo semente foi produzido usando 150 ml de meio LB mais sais incubados por 18h a 30oC, sob agitação de 200 rpm. A cepa utilizada foi 344 (B. thuringiensis var tolworthi ? pertencente ao Banco de Microorganismos da Embrapa). O pH foi medido a intervalos regulares. Após 96h de cultivo, o pH de todos os meios testados tenderam ao básico (entre 6,91 e 8,15), o maior número de esporos foi de 4,39 x 109 sporos/ml no meio 3, onde o teor de proteína usado foi o mais alto. A produção de massa celular foi maior no meio 3, com total acumulado de 39,3 g/l. A mortalidade de larvas de Spodoptera frugiperda (J.E. Smith) de dois dias de idade nos meios 3 e 4 foi de 100%. A CL50 para o meio 3 foi de 8,4 x 106 esporos/ml. Os meios alternativos usados promoveram crescimento satisfatório de Bt, sendo o meio 3 o mais promissor para ser usado na produção de biopesticida à base de Bt

The mixed capacitated arc routing problem with non-overlapping routes

Real world applications for vehicle collection or delivery along streets usually lead to arc routing problems, with additional and complicating constraints. In this paper we focus on arc routing with an additional constraint to identify vehicle service routes with a limited number of shared nodes, i.e. vehicle service routes with a limited number of intersections. This constraint leads to solutions that are better shaped for real application purposes. We propose a new problem, the bounded overlapping MCARP (BCARP), which is defined as the mixed capacitated arc routing problem (MCARP) with an additional constraint imposing an upper bound on the number of nodes that are common to different routes. The best feasible upper bound is obtained from a modified MCARP in which the minimization criteria is given by the overlapping of the routes. We show how to compute this bound by solving a simpler problem. To obtain feasible solutions for the bigger instances of the KARP heuristics are also proposed. Computational results taken from two well known instance sets show that, with only a small increase in total time traveled, the model BCARP produces solutions that are more attractive to implement in practice than those produced by the MCARP modelinfo:eu-repo/semantics/submittedVersio

Desenvolvimento de catalisadores magnéticos para despoluição de água contaminadas com pesticidas.

bitstream/CNPDIA-2009-09/11027/1/CiT39_2007.pd

Comparing and predicting inconsistency on positive and negative life experiences reports: which variables matter?

Most studies about life experiences and their long-term impact have relied on retrospective assessments and cross-sectional designs. However, there are concerns about the inconsistency of reports, which have been addressed in a limited scope. This study aimed to compare differences on inconsistency between positive and negative experiences to describe potential patterns and to identify sociodemographic, experiences-related and design-related predictors of inconsistency. Adults from community (N = 171) reported their life experiences twice, through self-report or interview. An overall trend of overreporting was found for positive and negative experiences. Additionally, inconsistency on positive experiences was higher than on negative although both variables were correlated. Regarding predictors of inconsistency, the model explained greater variance for negative experiences than for the positive ones. Nevertheless, most variables did not predict inconsistency, with few exceptions: impact for positive experiences, total of experiences for negative experiences, and time interval was marginally significant for both. Available data comparing inconsistency on positive and negative experiences as well as associated predictors are incipient. Overall, it seems that we know more about variables not involved in inconsistency than those that matter. Due to its relevancy, this issue should be further examined.This manuscript is part of a doctoral dissertation which had the support of the Portuguese Foundation for Science and Technology (FCT), through the PhD grant with the reference SFRH/BD/6022/2011, funded by POPH-QREN-Typology 4.1-Advanced Training–reimbursed by the European Social Fund and national funds from State Budget. This study was conducted at the Psychology Research Centre (CIPsi/UM) School of Psychology, University of Minho, supported by the Foundation for Science and Technology (FCT) through the Portuguese State Budget (UIDB/01662/2020)