Constraint-bounded design search

The design process requires continual checking of the consistency of design choices against given sets of goals that have been fulfilled. Such a check is generally performed by comparing abstract representations of design goals with these of the sought real building objects (RBO) resulting from complex intellectual activities closely related to the designer's culture and to the environment in which he operates. In this chapter we define a possible formalization of such representations concerning the goals and the RBO that are usually considered in the architectural design process by our culture in our environment. The representation of design goals is performed by expressing their objective aspects (requirements) and by defining their allowable values (performance specifications). The resulting system of requirements defines the set of allowable solutions and infers an abstract representation of the sought building objects (BO) that consists of the set of characteristics (attributes and relations) which are considered relevant to represent the particular kind of RBO with respect to the consistency check with design goals. The values related to such characteristics define the performances of the RBO while their set establishes its behaviour. Generally speaking, there is no single real object corresponding to an abstract representation but the whole class of the RBO that are equivalent with respect to the values assumed by the considered characteristics. The more we increase the number of these, as well as their specifications, the smaller the class becomes until it coincides with a single real object - given that the assessed specifications be fully consistent. On the other hand, the corresponding representation evolves to the total prefiguration of the RBO. It is not therefore possible to completely define a BO representation in advance since this is inferred by the considered goals and is itself a result of the design process. What can only be established in advance is that any set of characteristics assumed to represent any RBO consists of hierarchic, topological, geometrical and functional relations among the parts of the object at any level of aggregation (from components to space units, to building units, to the whole building) that we define representation structure (RS). Consequently the RS may be thought as the elementary structures that, by superposition and interaction, set up the abstract representation that best fit with design goals

Distraction Osteogenesis: Biological Principles and Its Application in Companion Animals

Distraction osteogenesis is a surgical technique widely used in orthopedic surgery for treatment of various pathological skeletal conditions, namely correction of limb-length discrepancies, angular deformity and treatment of distal and severely comminuted fractures, or bone defects through bone transport. The basic principle consists on the gradual distraction of two bone segments, previously submitted to a corticotomy and promptly fixated generally using of circular external skeletal fixation. New bone tissue is generated in the bone gap between the two segments. This review aims to describe the biological fundaments and principles of this technique, the surgical steps performed to attempt distraction osteogenesis, and its possible complications with main focus on its application in companion animals

Foundation of a computable solid modelling

Solid modelling and computational geometry are based on classical topology and geometry in which the basic predicates and operations, such as membership, subset inclusion, union and intersection, are not continuous and therefore not computable. But a sound computational framework for solids and geometry can only be built in a framework with computable predicates and operations. In practice, correctness of algorithms in computational geometry is usually proved using the unrealistic Real RAM machine model of computation, which allows comparison of real numbers, with the undesirable result that correct algorithms, when implemented, turn into unreliable programs. Here, we use a domaintheoretic approach to recursive analysis to develop the basis of an eective and realistic framework for solid modelling. This framework is equipped with a well-dened and realistic notion of computability which reects the observable properties of real solids. The basic predicates and operations o..

Transplantação renal : técnicas cirúrgicas

Objectivos: A transplantação renal é a forma de tratamento de eleição da doença renal crónica terminal. Este tratamento cirúrgico tem vindo a sofrer alterações ao longo dos anos, com vista a melhorar os resultados do mesmo, e diminuir as co-morbilidades associadas, sendo a técnica do procedimento o alvo deste estudo de revisão. Materiais e Métodos: Realizou-se uma revisão da literatura nesta área, recorrendo-se a livros e artigos publicados, bem como, à observação de procedimentos no Serviço de Urologia e Transplantação Renal dos Hospitais da Universidade de Coimbra, com início em Maio de 2010 e término em Março de 2011. Resultados: Da análise realizada, são apresentados dois grandes procedimentos: a nefrectomia do dador (vivo ou cadáver) e a implantação no receptor, composta pela incisão, colocação do enxerto, anastomose vascular e anastomose urinária. Cada um possui opções técnicas que são empregues por diferentes centros, e serão alvo de análise. Conclusões: Dentro destes passos, existem diferentes técnicas, todas elas possuindo vantagens e desvantagens, que não trazem um total consenso sobre o procedimento de eleição, pelo que, a escolha deve ser adequada ao doente e à experiência do centro.Purpose: Kidney transplantation is the treatment of choice for patients with end-stage renal disease. This surgical procedure has suffered some changes over the past decades to achieve better outcomes and less co-morbidity, being the goal of this study its technical aspects. Materials and Methods: From May 2010 to March 2011, a revision on the literature about this theme has been made, investigating books and articles published in this area. To enrich the study, renal transplants made by the Department of Urology and Renal Transplantation of Hospitais da Universidade de Coimbra have been carefully observed, and its procedure carefully analised. Results: From the investigation made, two main procedures will be presented: donor nephrectomy (living-donor and deceased-donor) and kidney implantation in the receptor, composed by the incision, kidney positioning, vascular and urinary anastomoses. Each one of these steps has different technical options, which will be object of analysis.Conclusions: In the steps mentioned before, there are different techniques to conceive them, each one with advantages and disadvantages, which do not achieve total consensus between transplantation centers. Thus, the procedure should be chosen according to the surgeons’ experience

Evaluation of feline permanent canine tooth mineral density using micro-computed tomography

The tooth is made up of three mineralized tissues, enamel, dentin, and cementum, which surround a non-mineralized tissue called the dental pulp. Micro-computed tomography (mCT) is an imaging technology based on X-rays that allows non-invasive visualization of objects at a microscopic scale, according to their radiopacity and in three dimensions (3D). Likewise, it allows the subsequent execution of morphological and quantitative analysis of the objects, such as, for example, the determination of the relative mineral density (MD). The present work aimed to describe the MD of feline teeth using mCT. The studied sample consisted of four European Shorthair cats, from which nine canine teeth were extracted per medical indication. These teeth were evaluated through dental radiography before and after their extraction. Using mCT and the CTAn software, the values of the relative mineral density of the root of each tooth and of specific segments corresponding to the coronal, middle, and apical thirds of the root were determined. Mean MD of root tissues was 1.374 ± 0040 g·cm−3, and of hard root, tissues was 1.402 ± 0.035 g·cm−3. Through mCT, it was possible to determine the mean MD values of feline canine teeth. The study of MD could become an ancillary method for the diagnosis and characterization of dental pathology.This work was funded by national funds through FCT—Foundation for Science and Technology, I.P., under the Scientific Employment Stimulus—Institutional Call-CEECINS/00127/2018 (J.F. Requicha) and supported by the projects UIDB/CVT/00772/2020 and LA/P/0059/2020

Dental pathology of the wild Iberian wolf (Canis lupus signatus): The study of a 20th century Portuguese museum collection

For some wild canids, such as the Iberian wolf, there is a lack of in-depth knowledge about dental pathology. We aimed to evaluate it, in a standardized manner, in specimens from a Portuguese museum collection. Sixty-five deceased specimens of wild Iberian wolves, 61 complete skulls and 4 mandibles, collected in Portugal between 1977 and 1995, were analyzed. Sample comprised 18 females, 24 males and 23 individuals of undetermined sex. Teeth were evaluated by visual observation and dental radiography for tooth wear, periodontitis, fractures and other dental lesions. We have found several causes for teeth absence: artefactual, secondary to periodontitis and agenesia. About 30% of the teeth showed signs of wear. Only a small (<13%) fraction of maxillary and mandibular teeth did not show periodontitis. The tooth 308 showed periodontitis in all males (p = 0.017) and the tooth 104 was significantly affected by this condition in females (p = 0.020). A significant relationship was found between females and tooth wear in three teeth. Periodontitis showed a significant association with tooth wear (p < 0.001) and fractures (p = 0.027). Tooth fractures were more frequent in the maxilla than in the mandible. Seven periapical lesions, seven root fusions and three specimens with malocclusion were identified in the collection. Results are discussed integrating information from diet, habitat, genetic and spatial behavior. Dental radiography is here proposed as an approach for the age estimation in archaeological canids. This research contributes to the knowledge of the dental disease in the largest wolf population in Western Europe, a target subspecies of multiple conservation measures.info:eu-repo/semantics/publishedVersio

Observation of coupled plasmon-polariton modes of plasmon waveguides for electromagnetic energy transport below the diffraction limit

We investigate the possibility of using arrays of closely spaced metal nanoparticles as plasmon waveguides for electromagnetic energy below the diffraction limit of light. Far-field spectroscopy on arrays of closely spaced 50 nm Au particles fabricated using electron beam lithography reveals the presence of near-field optical particle interactions that lead to shifts in the plasmon resonance frequencies for longitudinal and transverse excitations. We link this observation to a point-dipole model for energy transfer in plasmon waveguides and give an estimate of the expected group velocities and energy decay lengths for the fabricated structures. A near-field optical excitation and detection scheme for energy transport is proposed and demonstrated. The fabricated structures show a high propagation loss of about 3 dB / 15 nm which renders a direct experimental observation of energy transfer impossible. The nature of the loss and ways to decrease it by an order of magnitude are discussed. We also present finite-difference time-domain simulations on the energy transfer properties of plasmon waveguides

Solid Modeling

To appear in the Encyclopedia of Electrical and Electronics Engineering, Ed. J. Webster, John Wiley & Sons, 1999.A solid model is a digital representation of the geometry of an existing or envisioned physical object. Solid models are used in many industries, from entertainment to health care. They play a major role in the discrete-part manufacturing industries, where precise models of parts and assemblies are created using solid modeling software or more general computer-aided design (CAD) systems. Solid modeling is an interdisciplinary field that involves a growing number of areas. Its objectives evolved from a deep understanding of the practices and requirements of the targeted application domains. Its formulation and rigor are based on mathematical foundations derived from general and algebraic topology, and from Euclidean, differential, and algebraic geometry. The computational aspects of solid modeling deal with efficient data structures and algorithms, and benefit from recent developments in the field of computational geometry. Efficient processing is essential, because the complexity of industrial models is growing faster than the performance of commercial workstations. Techniques for modeling and analyzing surfaces and for computing their intersections are important in solid modeling. This area of research, sometimes called computer aided geometric design, has strong ties with numerical analysis and differential geometry. Graphic user-interface (GUI) techniques also play a crucial role in solid modeling, since they determine the overall usability of the modeler and impace the user's productivity. There have always been strong symbiotic links and overlaps between the solid modeling community and the computer graphics community. Solid modeling interfaces are based on efficient three-dimensional (3D) graphics techniques, whereas research in 3D graphics focuses on fast or photo-realistic rendering of complex scenes, often composed of solid models, and on realistic or artistic animations of non-rigid objects. A similar symbiotic relation with computer vision is regaining popularity, as many research efforts in vision are model-based and attempt to extract 3D models from images or video sequences of existing parts or scenes. These efforts are particularly important for solid modeling, because the cost of manually designing solid models of existing objects or scenes far excees the other costs (hardware, software, maintenance, and training) associated with solid modeling. Finally, the growing complexity of solid models and the growing need for collaboration, reusability of design, and interoperability of software require expertise in distributed databases, constraint management systems, optimization techniques, object linking standards, and internet protocols. This report provides a brief overview of the solid modeling field, its fundamental technologies, and some important applications