Rule-based production planning in flexible manufacturing systems

Production planning in flexible manufacturing may require the solution of a large-scale discrete-event dynamic stochastic optimization problem, due to the complexity of the system to be optimized, and to the occurrence of discrete events (new orders and hard failures). The production planning problem is here approached for a multistage multipart-type manufacturing shop, where each work cell can share its processing time among the different types of parts. The solution of this problem is obtained by an open-loop-feedback control strategy, updated each time a new event occurs. At each event time, two coupled problems are solved: 1) a product-order scheduling problem, conditioned on estimated values of the production capacities of all component work cells; and 2) a production-capacity planning problem, conditioned on predefined sequences of the product orders to be processed. In particular, the article aims at defining a production planning procedure that integrates both analytical tools, derived from mathematical programming, and knowledge-based rules, coming from experience. The objective is to formulate a hybrid (knowledge-based/analytical) planning architecture, and to analyze its use for multicell multipart-type manufacturing systems.     

Effects of amphipathic peptides,including presequences,on the functional integrity of rat liver mitochondrial membranes

A number of amphipathic peptides were tested for their effects on structural and functional properties of isolated rat liver mitochondria. The peptides included the matrix targeting sequence of subunit IV of (yeast) cytochromec oxidase. Titration experiments in which the mitochondria were incubated with increasing concentrations of the peptides revealed two major stages in the interaction. First, at low peptide/mitochondria ratios, peptide binding to the outer membrane occurred which was accompanied by gradual lysis of the outer membrane at higher ratios. The latter was deduced from the release of adenylate kinase, the classical marker enzyme of the intermembrane space. Secondly, at still higher peptide/mitochondria ratios, the permeability of the inner membrane progressively increased, as evidenced by measurements of respiratory control and of the membrane potential. Complete uncoupling of respiration seemed to precede dissipation of the membrane potential.     

Minimizing the effect of mineral nitrogen on biological nitrogen fixation in common bean by increasing nutrient levels

Although common bean (Phaseolus vulgaris L.) has good potential for N₂ fixation, some additional N provided through fertilizer usually is required for a maximum yield. In this study the suppressive effect of N on nodulation and N₂ fixation was evaluated in an unfertile soil under greenhouse conditions with different levels of soil fertility (low=no P, K and S additions; medium = 50, 63 and 10 mg kg^–1 soil and high = 200, 256 and 40 mg kg^–1 soil, respectively) and combined with 5, 15, 60 and 120 mg N kg^–1 soil of ¹⁵N-labelled urea. The overall average nodule number and weight increased under high fertility levels. At low N applications, nitrogen had a synergistic effect on N₂ fixation, by stimulating nodule formation, nitrogenase activity and plant growth. At high fertility and at the highest N rate (120 mg kg^–1 soil), the stimulatory effect of N fertilizer on N₂ fixation was still observed, increasing the amounts of N₂ fixed from 88 up to 375 mg N plant^–1. These results indicate that a suitable balance of soil nutrients is essential to obtain high N₂ fixation rates and yield in common beans.     

Mobilization of a Recombinant IncQ Plasmid between Bacteria on Agar and in Soil via Cotransfer or Retrotransfer

Mobilization of a genetically engineered IncQ plasmid, pSKTG, was studied in vitro and in sterile and nonsterile soils. In biparental and triparental filter matings, the mobilization frequencies of pSKTG were identical, and the plasmid was mobilized only in the presence of self-transmissible plasmid RP4p. In sterile soil, mobilization was probably limited by reduced cell-to-cell contact, since the frequencies of mobilization were approximately 100-fold lower than the frequencies in the filter matings. The transfer frequency of pSKTG in sterile soil when RP4p was present in the same strain was about 100-fold higher than the transfer frequency when RP4p was present in a separate strain. In studies in natural soil, pSKTG was also found to be transferred to indigenous bacteria. However, natural mobilization by genetic elements present in the indigenous soil microflora could not be detected. In vitro studies of natural transfer suggested that such genetic elements occur in soil bacteria.     

VAMP-2 and cellubrevin are expressed in pancreatic beta-cells and are essential for Ca(2+)-but not for GTP gamma S-induced insulin secretion.

VAMP proteins are important components of the machinery controlling docking and/or fusion of secretory vesicles with their target membrane. We investigated the expression of VAMP proteins in pancreatic beta-cells and their implication in the exocytosis of insulin. cDNA cloning revealed that VAMP-2 and cellubrevin, but not VAMP-1, are expressed in rat pancreatic islets and that their sequence is identical to that isolated from rat brain. Pancreatic beta-cells contain secretory granules that store and secrete insulin as well as synaptic-like microvesicles carrying gamma-aminobutyric acid. After subcellular fractionation on continuous sucrose gradients, VAMP-2 and cellubrevin were found to be associated with both types of secretory vesicle. The association of VAMP-2 with insulin-containing granules was confirmed by confocal microscopy of primary cultures of rat pancreatic beta-cells. Pretreatment of streptolysin-O permeabilized insulin-secreting cells with tetanus and botulinum B neurotoxins selectively cleaved VAMP-2 and cellubrevin and abolished Ca(2+)-induced insulin release (IC50 approximately 15 nM). By contrast, the pretreatment with tetanus and botulinum B neurotoxins did not prevent GTP gamma S-stimulated insulin secretion. Taken together, our results show that pancreatic beta-cells express VAMP-2 and cellubrevin and that one or both of these proteins selectively control Ca(2+)-mediated insulin secretion.     

An "artificial tongue" for calibrating solution flow characteristics of taste stimulus delivery systems

An "artificial tongue" is described which can be used to calibratethe stimulus delivery characteristics of flow systems for liquidtaste stimuli. The calibrator, which functions on the basisof conductance measurements, is used to ascertain the behaviourof certain test solutions in the flow system. The test solutionsare so prepared that they mimic the hydraulic properties ofthe stimulus solutions to be used. The special apparatus requiredis neither complex nor costly, and the procedures involved arestraightforward.     

Aeration: A simple method to control vitrification and improve in vitro culture of rare australian plants

Summary Aeration of tissue cultured rare Australian plantsConostylis wonganensis S.D. Hopper (Haemodoraceae);Diplolaena andrewsii Ostenf.;Drummondita ericoides Harvey (Rutaceae);Eremophila resinosa F. Muell. (Myoporaceae);Eucalyptus ‘graniticola’ (Myrtaceae);Lechenaultia pulvinaris C. Gardner (goodeniaceae); andSowerbaea multicaulis E. Pritzel (Liliaceae) has been found to reduce vitrification in sensitive species as well as significantly improving shoot quality and transfer to soil in most study species. A simple 7-mm hole with a double-layer insert of filter paper in the polypropylene screw lids of the culture vessel decreased shoot vitrification over a 4-wk culture period. The method has implications for facilitating the tissue culture of other rare Australian plants and reducing the occurrence of this developmental abnormality.     

Resistance of the AF-28 sorghum variety to Contarinia sorghicola

The variety AF-28 of Sorghum bicolor Pers and the hybrid R-1090 were compared in relation to the sorghum midge, Contarinia sorghicola (Coquillet), (Diptera: Cecidomyidae) in two counties of the State of São Paulo. They were compared in seven successive monthly trials beginning in September 1972. Averages of 252 and 137 adult flies emerged per head of the hybrid R-1090 in Campinas and Jaboticabal respectively, while 2.9 and 0.8 emerged from AF-28. The damage was graded with a visual scale from 0 to 4. Average damage grades of 3.5 and 3.3 were attributed to the hybrid R-1090 in Campinas and Jaboticabal respectively, while the variety AF-28 had averages of 0.5 and 0.3, respectively.

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Résumé La variété AF-28 et l'hybride R-1090 de Sorghum bicolor Pers. ont été comparés à différentes époques de l'année et en deux localités différentes de l'Etat de Sâo Paulo, Brésil.On n'a pas constaté d'interaction variété x époque ou variété x lieu.AF-28 a prouvé sa résistance à toutes les époques, aussi bien dans un lieu que dans l'autre; l'hybride par contre s'est montré grandement susceptible.Des moyennes de 252,2 et 136,7 mouches par panicule ont été observées pour l'hybride R-1090 à Campinas et à Jaboticabal contre 2,9 et 0,8 seulement par panicule de AF-28. Le préjudice a été estimé visuellement selon une échelle de 0 à 4. Des préjudices d'une valeur moyenne de 3,5 et 3,3 ont été attribués à l'hybride R-1090 à Campinas et à Jaboticabal respectivement, alors que simultanément la variété AF-28 ne subissait que des préjudices évalués à 0,5 et 0,3 respectivement.Quatre espèces de microhyménoptères parasites de Contarinia sorghicola ont été récoltées au cours de ce travail: Eupelmus popa et trois espèces différentes du genre Tetrastichus.

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Part of a thesis presented to the School of Sciences of Bauru for fulfilment of the requirement for the degree of Doctor of Science. This research was financed by the Project 72/1471 of the agreement UNIÃO-ESTADO-FAPESP and by CNPq Project 12910/73.     

Genomic surveillance of Nevada patients revealed prevalence of unique SARS-CoV-2 variants bearing mutations in the RdRp gene

Patients with signs of COVID-19 were tested through diagnostic RT-PCR for SARS-CoV-2 using RNA extracted from the nasopharyngeal/nasal swabs.To determine the variants of SARS-CoV-2 circulating in the state of Nevada,specimens from 200 COVID-19 patients were sequenced through our robust sequencing platform,which enabled sequencing of SARS-CoV-2 from specimens with even very low viral loads,without the need of culture-based amplification.High genome coverage allowed the identification of single and multi-nucleotide variants in SARS-CoV-2 in the community and their phylogenetic relationships with other variants present during the same period of the outbreak.We report the occurrence of a novel mutation at 323aa (314aa of orf1b) of nsp12 (RNA-dependent RNA polymerase) changed to phenylalanine(F) from proline (P),in the first reported isolate of SARS-CoV-2,Wuhan-Hu-1.This 323F variant was present at a very high frequency in Northern Nevada.Structural modeling determined this mutation in the interface domain,which is important for the association of accessory proteins required for the polymerase.In conclusion,we report the introduction of specific SARS-CoV-2 variants at very high frequency in distinct geographic locations,which is important for understanding the evolution and circulation of SARS-CoV-2variants of public health importance,while it circulates in humans.