Optimizations of Patch Antenna Arrays Using Genetic Algorithms Supported by the Multilevel Fast Multipole Algorithm

We present optimizations of patch antenna arrays using genetic algorithms and highly accurate full-wave solutions of the corresponding radiation problems with the multilevel fast multipole algorithm (MLFMA). Arrays of finite extent are analyzed by using MLFMA, which accounts for all mutual couplings between array elements efficiently and accurately. Using the superposition principle, the number of solutions required for the optimization of an array is reduced to the number of array elements, without resorting to any periodicity and similarity assumptions. Based on numerical experiments, genetic optimizations are improved by considering alternative mutation, crossover, and elitism mechanisms. We show that the developed optimization environment based on genetic algorithms and MLFMA provides efficient and effective optimizations of antenna excitations, which cannot be obtained with array-factor approaches, even for relatively simple arrays with identical elements

Accurate prediction of gene feedback circuit behavior from component properties

A basic assumption underlying synthetic biology is that analysis of genetic circuit elements, such as regulatory proteins and promoters, can be used to understand and predict the behavior of circuits containing those elements. To test this assumption, we used time‐lapse fluorescence microscopy to quantitatively analyze two autoregulatory negative feedback circuits. By measuring the gene regulation functions of the corresponding repressor–promoter interactions, we accurately predicted the expression level of the autoregulatory feedback loops, in molecular units. This demonstration that quantitative characterization of regulatory elements can predict the behavior of genetic circuits supports a fundamental requirement of synthetic biology

Distinct genealogies for plasmids and chromosome

An earlier perspective on the diversity of conjugative elements in microbes [1] attempted to provide a broad audience with an introductory overview of the arcane biology of mobile genetic elements and their terminologies. It might well have been entitled "Plasmids, ICEs, IMEs, and Other Mobile Elements for Dummies," but common sense prevailed. This perspective introduces two related articles in the current issue of PLOS Genetics [2,3] and might have equally aptly been entitled "Antibiotic-Resistant Plasmids and Their Epidemiology for Dummies.

Trace elements in Antarctic meteorites: Weathering and genetic information

Antarctic meteorite discoveries have created great scientific interest due to the large number of specimens recovered (approximately 7000) and because included are representatives of hitherto rare or unknown types. Antarctic meteorites are abundant because they have fallen over long periods and were preserved, transported, and concentrated by the ice sheets. The weathering effects on the Antarctic meteorites are described. Weathering effects of trace element contents of H5 chondrites were studied in detail. The results are examined. The properties of Antarctic finds and non-Antarctic falls are discussed

What traits are carried on mobile genetic elements, and why?

Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes

A genetic algorithm for the partial binary constraint satisfaction problem: an application to a frequency assignment problem

We describe a genetic algorithm for the partial constraint satisfaction problem. The typical elements of a genetic algorithm, selection, mutation and cross-over, are filled in with combinatorial ideas. For instance, cross-over of two solutions is performed by taking the one or two domain elements in the solutions of each of the variables as the complete domain of the variable. Then a branch-and-bound method is used for solving this small instance. When tested on a class of frequency assignment problems this genetic algorithm produced the best known solutions for all test problems. This feeds the idea that combinatorial ideas may well be useful in genetic algorithms.Economics ;

Information capacity of genetic regulatory elements

Changes in a cell's external or internal conditions are usually reflected in the concentrations of the relevant transcription factors. These proteins in turn modulate the expression levels of the genes under their control and sometimes need to perform non-trivial computations that integrate several inputs and affect multiple genes. At the same time, the activities of the regulated genes would fluctuate even if the inputs were held fixed, as a consequence of the intrinsic noise in the system, and such noise must fundamentally limit the reliability of any genetic computation. Here we use information theory to formalize the notion of information transmission in simple genetic regulatory elements in the presence of physically realistic noise sources. The dependence of this "channel capacity" on noise parameters, cooperativity and cost of making signaling molecules is explored systematically. We find that, at least in principle, capacities higher than one bit should be achievable and that consequently genetic regulation is not limited the use of binary, or "on-off", components.Comment: 17 pages, 9 figure

Genetic signature in mineral nutrition in oil palm (Elaeis guineensis Jacq.): A new panorama for high yielding materials at low fertiliser cost

Significant differences in mineral nutrition have been demonstrated between progenies and main categories at PT Socfindo (Jacquemard et al, 2002). New set of investigation has been conducted based on larger genetic background. It includes 489 progenies observed in 25 genetic trials planted in Aek Loba Timur Project and 63 commercial blocs covering around 3500 hectares dispatched through all PT Socfindo estates. Leaf contents in major elements constitute important genetic signature that allows characterization and individualization of nutritional level of each ALT project families according their genetic background. Observations achieved on commercial blocs confirm the signature of ALT project derived commercial categories. Some large groups show very distinct characteristics in their nutrient levels such as: Low Nitrogen - low Potassium Low Nitrogen - high Potassium High Nitrogen - low Potassium In addition, some high yielding families express specific behaviour linking Calcium to their Chlorine absorption, then limiting Potassium absorption. Relation-ship between all these elements is discussed. Providing of high yielding planting material more frugal in fertilizer input is discussed. This new panorama offered to research and oil palm sector is an added value on the way of sustainable palm oil. (Résumé d'auteur

The influence of the accessory genome on bacterial pathogen evolution

Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorise the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution

Mineral nutrition and its genetic signature in oil palm (Elaeis guineensis Jacq.): A possible panorama for high yielding materials at low fertiliser cost

Significant differences in the mineral nutrition have been demonstrated between progenies and the main categories at PT Socfindo (Jacquemard et al, 2002). A new set of investigations has been conducted based on a larger genetic background. It includes 489 progenies observed in 25 genetic trials planted at Aek Loba Timur Project and 63 commercial blocs covering around 3500 hectares dispatched through all the PT Socfindo estates. The leaf contents in the major elements constitute an important genetic signature that allows the characterization and the individualization of the nutritional level of each ALT project families according their genetic background. The observations achieved on the commercial blocs confirm the signature of ALT project derived commercial categories. Some large groups show very distinct characteristics in their nutrient levels such as: Low nitrogen - low potassium Low nitrogen - high potassium High nitrogen - low potassium In addition, some high yielding families express a specific behavior linking calcium to their chlorine absorption, then limiting the potassium absorption. The relation-ship between all these elements is discussed. Providing of high yielding planting material more frugal in fertilizer input is discussed. This possible panorama offered to research and oil palm sector is an added value on the way of sustainable palm oil. (Résumé d'auteur