Numerical simulation of skin transport using Parareal

In silico investigation of skin permeation is an important but also computationally demanding problem. To resolve all scales involved in full detail will not only require exascale computing capacities but also suitable parallel algorithms. This article investigates the applicability of the time-parallel Parareal algorithm to a brick and mortar setup, a precursory problem to skin permeation. The C++ library Lib4PrM implementing Parareal is combined with the UG4 simulation framework, which provides the spatial discretization and parallelization. The combination’s performance is studied with respect to convergence and speedup. It is confirmed that anisotropies in the domain and jumps in diffusion coefficients only have a minor impact on Parareal’s convergence. The influence of load imbalances in time due to differences in number of iterations required by the spatial solver as well as spatio-temporal weak scaling is discussed

Coupled aquaponics systems

Coupled aquaponics is the archetype form of aquaponics. The technical complexity increases with the scale of production and required water treatment, e.g. filtration, UV light for microbial control, automatic controlled feeding, computerization and biosecurity. Upscaling is realized through multiunit systems that allow staggered fish production, parallel cultivation of different plants and application of several hydroponic subsystems. The main task of coupled aquaponics is the purification of aquaculture process water through integration of plants which add economic benefits when selecting suitable species like herbs, medicinal plants or ornamentals. Thus, coupled aquaponics with closed water recirculation systems has a particular role to fulfil. Under fully closed recirculation of nutrient enriched water, the symbiotic community of fish, plants and bacteria can result in higher yields compared with stand-alone fish production and/or plant cultivation. Fish and plant choices are highly diverse and only limited by water quality parameters, strongly influenced by fish feed, the plant cultivation area and component ratios that are often not ideal. Carps, tilapia and catfish are most commonly used, though more sensitive fish species and crayfish have been applied. Polyponics and additional fertilizers are methods to improve plant quality in the case of growth deficiencies, boosting plant production and increasing total yield. The main advantages of coupled aquaponics are in the most efficient use of resources such as feed for nutrient input, phosphorous, water and energy as well as in an increase of fish welfare. The multivariate system design approach allows coupled aquaponics to be installed in all geographic regions, from the high latitudes to arid and desert regions, with specific adaptation to the local environmental conditions. This chapter provides an overview of the historical development, general system design, upscaling, saline and brackish water systems, fish and plant choices as well as management issues of coupled aquaponics especially in Europe

Laboratory spawning of the purple snail Plicopurpura pansa (Gastropoda: Muricidae)

The spawning of the muricid gastropod Plicopurpura pansa in the laboratory at 22-23°C is described. Females deposited 1-20 capsules daily for at least 20 weeks, and produced up to 150 capsules each per spawning season. During spawning, egg clusters were formed consisting of hundreds of capsules of different ages deposited by different females. Each egg capsule contained an average of 436 embryos (± s.d. 213.6, range: 95- 1 092, n = 50). Embryos developed without nurse eggs. After six to eight weeks of intracapsular, lecithotrophic development, planktotrophic veligers hatched with two fully developed velar lobesSe describe el desove del gasterópodo Plicopurpura pansa (Gould, 1853) (Gastropoda, Prosobranchia, Muricidae) a 22-23°C en el laboratorio. Cada hembra depositó diariamente de 1 a 20 cápsulas por lo menos durante 20 semanas y produjo hasta 150 cápsulas durante la estación de reproducción. Durante el tiempo de desove se formaron agrupaciones de cientos de cápsulas de diferentes edades y diferentes hembras. Cada cápsula contenía, según del tamaño, en promedio 436 embriones (± s.d. 213.6, ámbito: 95-1 092, n=50). Los embriones se desarrollaron sin huevos nutricios. Después de seis a ocho semanas del desarrollo lecitotrófico intracapsular eclosionaron larvas veliger planctotróficas completamente desarrolladas con dos velum de forma lobulad

Pr\ue9sence de \uab Cladium mariscus \ubb (L.) R. Br. et Scirpus lacustris L. dans la presqu\u27\ueele du Cap Vert

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Embryonic and intracapsular larval development of Plicopurpura pansa (Gould, 1853) (Prosobranchia, Muricidae) under laboratory conditions

The embryonic development of the marine muricid Plicopurpura pansa (Gould, 1853) until hatching is described. Each female spawned about 150 egg capsules in a 10-week period. The egg showed spiral segmentation, followed by gastrulation through epiboly, the formation of a non-typical trochophore and veliger larva. The embryos fed on the egg yolk. Nurse eggs were not observed. In 13% of the egg capsules, different embryonic or larval stages of development were found in the same capsule. At 21–23ºC the intracapsular development was completed with the hatching of planktotrophic veliger larvae after a period of 5 to 8 weeks

Component-Tree Simplification through Fast Alpha Cuts

Tree-based hierarchical image representations are commonly used in connected morphological image filtering, segmentation and multi-scale analysis. In the case of component trees, filtering is generally based on thresholding single attributes computed for all the nodes in the tree. Alternatively, so-called shapings are used, which rely on building a component tree of a component tree to filter the image. Neither method is practical when using vector attributes. In this case, more complicated machine learning methods are required, including clustering methods. In this paper I present a simple, fast hierarchical clustering algorithm based on cuts of α-trees to simplify and filter component trees