On the distribution of Percnon gibbesi (H. Milne Edwards, 1853) (Crustacea, Decapoda, Plagusiidae) along the Tunisian coast

The subtropical crab, Percnon gibbesi is established along the Tunisian coasts. This crab was recorded by underwater observation from Malloula, Tabarka, El-Haouaria, Yasmine Hammamet, Monastir marina and the Kuriat Islands. These new observations increase the known distribution of P. gibbesi in the south Mediterranean basin

Benign osteoblastoma in an unusual mastoid location

SummaryIntroductionBenign osteoblastoma (OB) is an unusual primary bone tumor. The preferred locations are the posterior arch of vertebrae and long bones. We report herein an extremely rare location of an OB in the mastoid process of the temporal bone.Case reportA 22-year-old woman presented with painful left retro-auricular swelling. Computed tomography features were suggestive of an aggressive osteolytic lesion of the left mastoid. The pathologic examination of bone curettage material revealed a benign OB. A complete resection of the tumor was performed later, with no evidence of recurrence at 1 year.Discussion/ConclusionTo our knowledge, this is the 14th reported case of OB confined to the mastoid process of temporal bone. Its histological diagnosis can be difficult and osteosarcoma is its principal differential diagnosis. Although generally regarded as benign, OB has potential for recurrence and local invasion. As such, complete resection, whenever possible, is preferred over conventional curettage

Review of alien marine macrophytes in Tunisia

In the present study, the list of alien marine macrophytes introduced into Tunisia was updated in the light of available data and new observations. A total of 27 alien marine macrophytes have been recorded so far from Tunisia: 18 Rhodophyta, 3 Ochrophyta, 5 Chlorophyta and 1 Magnoliophyta. For each species, the locality (-ies), the year (or) period and the source of the first observation in Tunisia are given. The distribution and the status (casual, cryptogenic, established or questionable) of species in Tunisia were evaluated and, where appropriate, discussed. Among them, Hypnea cornuta is reported for the first time from Tunisia. Fourteen alien marine macrophytes are established, whereas seven cryptogenic and two casual species require further investigation. Eleven species are considered as invasive or potentially invasive in the Mediterranean Sea: Acrothamnion preissii, Asparagopsis armata, A. taxiformis Indo-Pacific lineage, Hypnea cornuta, Lophocladia lallemandii, Womersleyella setacea, Caulerpa chemnitzia, C. cylindracea, C. taxifolia, Codium fragile subsp. fragile and Halophila stipulacea. Finally, the case of four questionable species is also discussed.The project “MAnagement of Port areas in the MEDiterranean Sea Basin (MAPMED)” has been funded by ENPI CBC MED Cross-Border Cooperation. This publication has been produced with the financial assistance of the European Union under the ENPI CBC Mediterranean Sea Basin Programme

Unpublished Mediterranean records of marine alien and cryptogenic species

Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta

From Architectured Materials to Large-Scale Additive Manufacturing

The classical material-by-design approach has been extensively perfected by materials scientists, while engineers have been optimising structures geometrically for centuries. The purpose of architectured materials is to build bridges across themicroscale ofmaterials and themacroscale of engineering structures, to put some geometry in the microstructure. This is a paradigm shift. Materials cannot be considered monolithic anymore. Any set of materials functions, even antagonistic ones, can be envisaged in the future. In this paper, we intend to demonstrate the pertinence of computation for developing architectured materials, and the not-so-incidental outcome which led us to developing large-scale additive manufacturing for architectural applications

Multigrid Implementation of Cellular Automata for Topology Optimisation of Continuum Structures with Design Dependent loads

Topology optimisation of continuum structures has become mature enough to be often applied in industry and continues to attract the attention of researchers and software companies in various engineering fields. Traditionally, most available algorithms for solving topology optimisation problems are based on the global solution approach and require a large number of costly analyses. An alternative methodology, based on cellular automata (CA) and accelerated with a multigrid discretisation scheme, can be a good candidate to solve topology optimisation problems in a reasonable amount of computational time. The main advantages of using CA paradigm in structural design are the local analysis and design resolutions, and its parallel nature. The multigrid acceleration method is used to improve its efficiency. This innovative approach offers a new paradigm for design and analysis with higher efficiency compared to existing design optimisation algorithms. In this thesis, the topology optimisation of continuum structures with design-dependent loads is solved using a multigrid accelerated cellular automata algorithm. The CA paradigm is applied to two and three dimensional continuum topology optimisation problems. An optimisation formulation based on minimum compliance design subject to a volume constraint is used in the present work. The cellular automata based design scheme uses local update(s) rules for both field variables (displacements) and design variables (cell densities). The analysis rules are derived from the principle of minimum total potential energy, and the design rules are derived based on continuous optimality criteria interpreted as local Kuhn-Tucker conditions. Numerical experiments demonstrate the robustness of the proposed CA algorithm to solve topology optimisation problems at the expense of slow convergence. The deterioration of CA convergence rate is due to slow propagation of information from cell to cell as the number of variables increases. A methodology based on multigrid scheme is used to accelerate the CA design algorithm. The multigrid acceleration scheme uses different discretisation levels of grids. The CA iterations on the finest grid are coupled with the iterations of the correction solution on the coarse grids. The multigrid accelerated CA algorithm is demonstrated to be a powerful tool for solving topology optimisation problems compared to other algorithms based on finite element analysis. The computational cost using this scheme is found to be proportional to the number of cells. The topology optimisation of continuum structures is also performed under the influence of design-dependent loads. A direct density based method that does not involve explicit construction of the loading surfaces is developed to define the design-dependent loads. The optimization problem is solved by the modified Method of Moving Asymptotes coupled with line search (MMALS), and by multigrid accelerated CA algorithms. An explicit constraint is added to the formulation to lead a design to a close pure black/white solution. Numerical examples demonstrate that the multigrid accelerated CA algorithm convergence is more stable and more robust than the MMALS algorithm. The proposed algorithms demonstrates the effect of design-dependent loading onto the topology optimisation problem as illustrated by creating extra elements, shape modifications or void appearing.Aerospace StructureAerospace Engineerin

Cystectomie partielle pour un neurosarcome primitif de la vessie: A propos d\'un cas

Les sarcomes génito-urinaires sont rares. Le leiomyosarcome et le rhabdomyosarcome sont les types histologiques les plus fréquemment observés. L\'origine nerveuse de ces sarcomes est exceptionnelle. Un diagnostic précoce et une exérèse complète de la tumeur permettent d\'améliorer le pronostic. Nous rapportons un cas de neurosarcome primitif de la vessie traité par une cystectomie partielle sus-trigonale. L\'évolution a été favorable avec un recul de 9 ans. Génito-urinary sarcomas are rare. Leiomyosarcomas and rhabdomyosarcomas are the histological types most frequently observed. The nervous origin of these sarcomas is exceptional. Early diagnosis and a complete resection of the tumor are necessary to improve the prognosis. We herein report the case of a primary neurosarcoma of the urinary bladder treated by partial cystectomy. At 9 years follow-up the patient is disease-free and has completed two pregnancies without any adverse events. Keywords: neurosarcome, vessie, cystectomie partielleAfrican Journal of Urology Vol. 13 (3) 2007: pp. 231-23

Wind load effect in topology optimization problems

Aerospace Engineerin

Wind load modeling for topology optimization of continuum structures

Topology optimization of two and three dimensional structures subject to dead and wind loading is considered. The wind loading is introduced into the formulation by using standard expressions for the drag force, and a strategy is devised so that wind pressure is ignored where there is no surface obstructing the wind. A minimum compliance design formulation is constructed subject to a volume constraint using the Solid Isotropic Material with Penalization model. The optimization problem is solved using the Method of Moving Asymptotes, modified by including a line search and by changing the formula for the update of asymptotes. To obtain black/white design, intermediate density values, which are used as design variables, are controlled by imposing an explicit constraint. Numerical examples of a windmill structure demonstrate that the proposed formulation rationally incorporates the effect of wind loading into the topology optimization problem as illustrated by void appearing in the optimal structure.Aerospace Structures & Design MethodologyAerospace Engineerin