Engineering Flow and Design

The importance of design in natural and engineered flow systems is undisputed. It is not only essential to life, but also plays a crucial role in our technological world. In Nature, it arises organically, spontaneously, and is the constructal path for systems to persist in time. The generation of the best design is the target of engineered flow systems. Fluid dynamics and thermodynamics have played a crucial role in the search for these flow designs. Analytical, numerical (CFD) and experimental studies played crucial roles in many technological breakthroughs. They provide the frameworks for understanding, simulating and interpreting flow phenomena. The collection of the articles in this issue, along with a complementary and expansive volume devoted to the same subject, reflect and reaffirm the importance and relevance of the study of flow design in natural and man-made flow systems in the twenty-first century

A computationally efficient method for calculating the maximum conductance of disordered networks: Application to 1-dimensional conductors

Random networks of carbon nanotubes and metallic nanowires have shown to be very useful in the production of transparent, conducting films. The electronic transport on the film depends considerably on the network properties, and on the inter-wire coupling. Here we present a simple, computationally efficient method for the calculation of conductance on random nanostructured networks. The method is implemented on metallic nanowire networks, which are described within a single-orbital tight binding Hamiltonian, and the conductance is calculated with the Kubo formula. We show how the network conductance depends on the average number of connections per wire, and on the number of wires connected to the electrodes. We also show the effect of the inter-/intra-wire hopping ratio on the conductance through the network. Furthermore, we argue that this type of calculation is easily extendable to account for the upper conductivity of realistic films spanned by tunneling networks. When compared to experimental measurements, this quantity provides a clear indication of how much room is available for improving the film conductivity.Comment: 7 pages, 5 figure

Sometimes hard to swallow: Attempted feeding on a porcupinefish results in death of both predator and prey

Predator-prey relationships are critical components of population dynamics across all ecosystems. Interactions between predators and dangerous prey are especially likely to result in a co-evolutionary arms race. To avoid predation, porcupinefishes (Diodontidae) present a suite of physical and chemical defences, including spines, inflation, and the potent neurotoxin, tetrodotoxin, which is concentrated in the internal organs. A failed predation attempt is described here on a longspined porcupinefish, Diodon holocanthus, by a benthopelagic predator, Carangoides fulvoguttatus, resulting in the death of both the predator and the prey.

The first complete mitochondrial genomes of sawtail surgeonfishes (Acanthuridae: Prionurus)

© 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Surgeonfishes of the family Acanthuridae are primarily large-bodied herbivores that provide critical ecosystem services to coral reefs. Five out of the six genera that comprise the family have had mitochondrial genomes sequenced, with the exception of the genus Prionurus. Here, for the first time, we assemble and annotate the mitochondrial genomes of two sawtail surgeonfishes. The circular genomes of P. biafraensis and P. laticlavius are 16,552 bp and 16,531 bp in length, respectively, and contain 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region. Gene arrangement and codon usage were similar to reported mitochondrial genomes of other surgeonfish genera, and a phylogenetic analysis of protein-coding genes recovers a topology for Acanthuridae that is consistent with nuclear analyses

Branching in fluidic networks with permeable walls: an extension of Hess-Murray’s law

The branching of fluidic networks becomes a subject of great interest due to its importance in understanding the behavior of branching networks in biology (cardiovascular and bronchial systems, river basins, the structure of plants and trees, etc..), as well as for the biomimetic design of engineering systems [1, 2]. The successive division of tubes and their hierarchical structure are distinctive features of tree-shaped networks. As the network progresses, tubes become smaller, both in length and diameter with the successive division of tubes. The design of these networks is generally assumed as being described by the Hess-Murray’s law. This paper addresses a fundamental issue of distributing a fluid flow in a network of vessels with permeable walls

Tosanoides aphrodite, a new species from mesophotic coral ecosystems of St. Paul’s Rocks, Mid Atlantic Ridge (Perciformes, Serranidae, Anthiadinae)

During a recent expedition to St. Paul’s Rocks, Atlantic Ocean, a distinctive and previously unknown species of Anthiadinae was collected at a depth of 120 m. A genetic analysis indicated the undescribed species is a member of the genus Tosanoides, which was only known to occur in the Pacific Ocean. This new taxon is distinguishable from all other Tosanoides species by the following combination of characters: soft dorsal fin rays 15–16; anal fin rays 9; ventral scale rows 9–10; last dorsal spine the longest (instead first through fourth). Here Tosanoides aphrodite sp. n. is described and illustrated, only known from St. Paul’s Rocks

Ecological traits influencing range expansion across large oceanic dispersal barriers: insights from tropical Atlantic reef fishes

How do biogeographically different provinces arise in response to oceanic barriers to dispersal? Here, we analyse how traits related to the pelagic dispersal and adult biology of 985 tropical reef fish species correlate with their establishing populations on both sides of two Atlantic marine barriers: the Mid-Atlantic Barrier (MAB) and the Amazon-Orinoco Plume (AOP). Generalized linear mixed-effects models indicate that predictors for successful barrier crossing are the ability to raft with flotsam for the deep-water MAB, non-reef habitat usage for the freshwater and sediment-rich AOP, and large adult-size and large latitudinal-range for both barriers. Variation in larval-development mode, often thought to be broadly related to larval-dispersal potential, is not a significant predictor in either case. Many more species of greater taxonomic diversity cross the AOP than the MAB. Rafters readily cross both barriers but represent a much smaller proportion of AOP crossers than MAB crossers. Successful establishment after crossing both barriers may be facilitated by broad environmental tolerance associated with large body size and wide latitudinal-range. These results highlight the need to look beyond larval-dispersal potential and assess adult-biology traits when assessing determinants of successful movements across marine barriers.International Macquarie University; Australian Research Council; Smithsonian Tropical Research Institute; National Geographic Society [7937-05]; CNPq; NSF [DEB-0072909]; University of Californi

Whole-genome assembly of the coral reef Pearlscale Pygmy Angelfish (Centropyge vrolikii)

The diversity of DNA sequencing methods and algorithms for genome assemblies presents scientists with a bewildering array of choices. Here, we construct and compare eight candidate assemblies combining overlapping shotgun read data, mate-pair and Chicago libraries and four different genome assemblers to produce a high-quality draft genome of the iconic coral reef Pearlscale Pygmy Angelfish, Centropyge vrolikii (family Pomacanthidae). The best candidate assembly combined all four data types and had a scaffold N50 127.5 times higher than the candidate assembly obtained from shotgun data only. Our best candidate assembly had a scaffold N50 of 8.97 Mb, contig N50 of 189,827, and 97.4% complete for BUSCO v2 (Actinopterygii set) and 95.6% complete for CEGMA matches. These contiguity and accuracy scores are higher than those of any other fish assembly released to date that did not apply linkage map information, including those based on more expensive long-read sequencing data. Our analysis of how different data types improve assembly quality will help others choose the most appropriate de novo genome sequencing strategy based on resources and target applications. Furthermore, the draft genome of the Pearlscale Pygmy angelfish will play an important role in future studies of coral reef fish evolution, diversity and conservationUC Berkeley | Ref. S10RR029668UC Berkeley | Ref. S10RR02730

Influence of the source of pollen on the oil content of maize grains

Os efeitos da fonte polinizadora sobre a percentagem de óleo em milho (Zea mays L.) foram avaliados em grãos provenientes de espigas autofecundadas e de polinização livre. Ambos os tipos de espigas foram obtidos de uma mesma planta, a fim de evitar os efeitos do citoplasma e do genoma materno. Foi usado o germoplasma de milho ESALQ VF 1, de grãos do tipo duro e de cor de laranja. Os resultados obtidos pela análise direta do conteúdo de óleo dos grãos revelaram uma depressão endogâmica de 4%, indicando a participação direta da fonte polinizadora no germoplasma estudado. Em programas de melhoramento, visando o aumento do conteúdo de óleo nos grãos de milho, neste germoplasma, as progênies poderão ser selecionadas, tanto através de sementes autofecundadas, como de polinização livre, pois a correlação linear entre os dois tipos de sementes foi elevada e positiva (r = 0,67**). Contudo, o uso de sementes de polinização livre proporciona menores custos operacionais ao programa. Além de possibilitar o ganho de uma geração, exibe considerável variabilidade genética entre sementes da mesma espiga.The present study evaluated the effects of source of pollen on the oll content of maize grains (Zea mays L.). Seed was used from two ears from the same plant, one that was self-fertilized and the other one open-pollinated. The work was conducted with germplasm ESALQ VF 1, an orange-coloured, hard grain type. The results of the analysis of oil content showed that there was an inbreeding depression of 4%, indicating the effective participation of source of pollen in the germplasm studied. In improvement programs to increase the oil content in maize grains, in this germplasm, progenies can be selected either through self-fertilized seeds or by open-pollination since the linear correlation between the two types of seeds was high and positive (r = 0.67**). The use of open-pollinated seed would mean lower operating costs in the program. Since this characteristic is being determined by the genotype of its own seed, it represents available genetic variation between seed of the same ear