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An extension of integral equation time-domain analysis to treat electromagnetic scattering from imperfect conductors embedded in a dielectric is presented. It employs isoparametric curvilinear representations, and an implicit timestepping approach is used to achieve stability. The principal difficulties arise from the diffusive 'wake' term which the finite conductivity introduces into the Green function. The consequent computational complexity and costs, both significantly greater than for perfectly conducting scatterers, are discussed. Examples of the application of the methods are presented. Index Terms--Conducting bodies, electromagnetic scattering, integral equation methods, time-domain analysis.

People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species. Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.3 of SBOL Visual, which builds on the prior SBOL Visual 2.2 in several ways. First, the specification now includes higher-level “interactions with interactions,” such as an inducer molecule stimulating a repression interaction. Second, binding with a nucleic acid backbone can be shown by overlapping glyphs, as with other molecular complexes. Finally, a new “unspecified interaction” glyph is added for visualizing interactions whose nature is unknown, the “insulator” glyph is deprecated in favor of a new “inert DNA spacer” glyph, and the polypeptide region glyph is recommended for showing 2A sequences.

People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species. Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.2 of SBOL Visual, which builds on the prior SBOL Visual 2.1 in several ways. First, the grounding of molecular species glyphs is changed from BioPAX to SBO, aligning with the use of SBO terms for interaction glyphs. Second, new glyphs are added for proteins, introns, and polypeptide regions (e. g., protein domains), the prior recommended macromolecule glyph is deprecated in favor of its alternative, and small polygons are introduced as alternative glyphs for simple chemicals.

People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species . Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.1 of SBOL Visual, which builds on the prior SBOL Visual 2.0 standard by expanding diagram syntax to include methods for showing modular structure and mappings between elements of a system, interactions arrows that can split or join (with the glyph at the split or join indicating either superposition or a chemical process), and adding new glyphs for indicating genomic context (e.g., integration into a plasmid or genome) and for stop codons.

Synthetic biology builds upon the techniques and successes of genetics, molecular biology, and metabolic engineering by applying engineering principles to the design of biological systems. The field still faces substantial challenges, including long development times, high rates of failure, and poor reproducibility. One method to ameliorate these problems is to improve the exchange of information about designed systems between laboratories. The synthetic biology open language (SBOL) has been developed as a standard to support the specification and exchange of biological design information in synthetic biology, filling a need not satisfied by other pre-existing standards. This document details version 2.3.0 of SBOL, which builds upon version 2.2.0 published in last year’s JIB Standards in Systems Biology special issue. In particular, SBOL 2.3.0 includes means of succinctly representing sequence modifications, such as insertion, deletion, and replacement, an extension to support organization and attachment of experimental data derived from designs, and an extension for describing numerical parameters of design elements. The new version also includes specifying types of synthetic biology activities, unambiguous locations for sequences with multiple encodings, refinement of a number of validation rules, improved figures and examples, and clarification on a number of issues related to the use of external ontology terms.

Synthetic biology builds upon the techniques and successes of genetics, molecular biology, and metabolic engineering by applying engineering principles to the design of biological systems. The field still faces substantial challenges, including long development times, high rates of failure, and poor reproducibility. One method to ameliorate these problems would be to improve the exchange of information about designed systems between laboratories. The Synthetic Biology Open Language (SBOL) has been developed as a standard to support the specification and exchange of biological design information in synthetic biology, filling a need not satisfied by other pre-existing standards. This document details version 2.1 of SBOL that builds upon version 2.0 published in last year’s JIB special issue. In particular, SBOL 2.1 includes improved rules for what constitutes a valid SBOL document, new role fields to simplify the expression of sequence features and how components are used in context, and new best practices descriptions to improve the exchange of basic sequence topology information and the description of genetic design provenance, as well as miscellaneous other minor improvements.

Synthetic biology builds upon the techniques and successes of genetics, molecular biology, and metabolic engineering by applying engineering principles to the design of biological systems. The field still faces substantial challenges, including long development times, high rates of failure, and poor reproducibility. One method to ameliorate these problems would be to improve the exchange of information about designed systems between laboratories. The synthetic biology open language (SBOL) has been developed as a standard to support the specification and exchange of biological design information in synthetic biology, filling a need not satisfied by other pre-existing standards. This document details version 2.2.0 of SBOL that builds upon version 2.1.0 published in last year’s JIB special issue. In particular, SBOL 2.2.0 includes improved description and validation rules for genetic design provenance, an extension to support combinatorial genetic designs, a new class to add non-SBOL data as attachments, a new class for genetic design implementations, and a description of a methodology to describe the entire design-build-test-learn cycle within the SBOL data model.

People who are engineering biological organisms often find it useful to communicate in diagrams, both about the structure of the nucleic acid sequences that they are engineering and about the functional relationships between sequence features and other molecular species. Some typical practices and conventions have begun to emerge for such diagrams. The Synthetic Biology Open Language Visual (SBOL Visual) has been developed as a standard for organizing and systematizing such conventions in order to produce a coherent language for expressing the structure and function of genetic designs. This document details version 2.0 of SBOL Visual, which builds on the prior SBOL Visual 1.0 standard by expanding diagram syntax to include functional interactions and molecular species, making the relationship between diagrams and the SBOL data model explicit, supporting families of symbol variants, clarifying a number of requirements and best practices, and significantly expanding the collection of diagram glyphs.

Knowledge of the genus Haematococcus is briefly summarized, the existence in Southern Africa of many habitats suitable to the alga indicated, and the occurrence of the various species recorded. The cosmopolitan species H. lacurtris is widespread. In addition two new species are described: H. capensis with several varieties and forms already recorded from many localities in both the Western and Eastern Provinces and H. zimbabwiensis as yet known only from Zimbabwe. The life history of H. capensis, described in detail, is closely comparable with those of H. buetschlii and H. droebakensis. Material of the latter collected at Stonehenge has been kept in culture at the Cape and in Grahamstown for many years. In all three species sexual reproduction is by means of gametes formed in motile cells, and asexually formed resting cells are rare. Special attention has been given to the behaviour of H. lacustris from numerous sources grown under varying conditions; the dominance of the motile cell in building up the population in this as in the other species is stressed. Reproduction by means of asexually formed non-motile cells, occasional in the other species, has developed to such a degree in this species that it has largely replaced sexual reproduction which is comparatively rare, the gametes being formed not in motile cells but on germination of asexually formed resting spores. Gametes and zygotes have been found once in nature near Grahamstown. Partial success in applying Peeble's method for inducing sexual reproduction has yielded indications of the existence of two types of naked swarmers: the smaller, gametes which conjugate to form zygotes, the larger of the nature of accessory cells. These develop without conjugation, forming resting spores which eventually germinate producing normal motile cells. The taxonomy of the genus is discussed, the combination Haematococcus lacustris (Girod.) Rostafinski is maintained and the division of the genus into two genera proposed by Droop considered. Careful comparative studies of the species leads to the conclusion that such a division is not justified and the genus Balticola proposed by Droop is therefore rejected. A key to the species of Haematococcus is included. [ABSTRACT FROM PUBLISHER]

This paper* deals with a new type of green alga originally found on the Cape Flats and since obtained in the United States of America and Australia. Initially identified as a second species of Volvulina Playfair, the considerations which led to the establishment of a distinct genus, Astrephomene, including the appearance from the Flats of Volvulina itself, are summarized, Playfair's description analysed and the resultant conclusion that he was dealing with two different algae mentioned; the steps that resulted in the verification of this conclusion are indicated. The two methods of culture used in the investigation are described. An amended description of Volvulina steinii Playfair is given and the results of observations made during a study of the alga in culture are recorded. The genus Astrephomene with the single species A. gubernaculifera is defined, a full account of its structure and life history given and its similarity to and difference from Volvulina pointed out, particularly the absence of inversion and the possession of a unique directive organ, the ‘rudder’. The results of cultures selected to illustrate certain points are summarized and the value of soil cultures in the study of algae emphasized. The validity of Playfair's genus is discussed, references by Stein and Carter are analysed and the possibility of its occurrence in India suggested. The relation between nutrition and certain features common to both algae is discussed, the characters of the two compared and the taxonomic position of each considered. A new family of the Volvocales, astrephomenaceae, is proposed for the reception of the monotypic genus, Astrephomene. [ABSTRACT FROM PUBLISHER]