Anti-aliasing with stratified B-spline filters of arbitrary degree

A simple and elegant method is presented to perform anti-aliasing in raytraced images. The method uses stratified sampling to reduce the occurrence of artefacts in an image and features a B-spline filter to compute the final luminous intensity at each pixel. The method is scalable through the specification of the filter degree. A B-spline filter of degree one amounts to a simple anti-aliasing scheme with box filtering. Increasing the degree of the B-spline generates progressively smoother filters. Computation of the filter values is done in a recursive way, as part of a sequence of Newton-Raphson iterations, to obtain the optimal sample positions in screen space. The proposed method can perform both anti-aliasing in space and in time, the latter being more commonly known as motion blur. We show an application of the method to the ray casting of implicit procedural surfaces

Doença de Fahr : a propósito de um caso clínico

A doença de Fahr é uma doença neuropsiquiátrica rara caracterizada por calcificação dos gânglios basais, podendo-se manifestar por alterações do movimento, demência e doenças afectivas. O diagnóstico é feito através de métodos imagiológicos (TAC ou RMN CE). É apresentado um caso clínico de doença de Fahr, em que os primeiros sintomas de doença foram alterações do humor

Novos dados na relação entre córtex pré-frontal e doença bipolar

Apresentam-se alguns dados de novos estudos que vêm evidenciar a relação próxima entre córtex préfrontal e neurofisiologia da doença bipolar. As alterações generalizadas mais frequentes em estudos imagiológicos são hiperintensidades da substância branca subcortical e periventricular. No córtex pré-frontal, a nível subregional, encontra-se uma diminuição do volume da substância cinzenta, com perda de células gliais e atrofia celular. Uma das áreas mais afectadas por esta redução é a área subgenual. Em estudos funcionais encontra-se diminuição da activação do lobo pré-frontal em algumas tarefas. Outros estudos procuraram também relacionar efeitos de fármacos com algumas das alterações encontradas. Há grande variabilidade nos resultados, que pode ser explicada por vários factores, como a heterogeneidade dos doentes ou dos métodos de imagem

Benthic ecology of semi-natural coastal lagoons, in the Ria Formosa (Southern Portugal), Exposed to different water renewal regimes

Several studies in semi-natural coastal lagoons in the Ria Formosa lagoonal system have been carried out. These man-made water reservoirs behave as small lagoons with one opening to the tidal channels, which may be intermittent. Because of their size, these reservoirs are ideal sites for ecological studies. Water quality and macrobenthic fauna were analysed in five water reservoirs. All reservoirs received the same incoming water through a tidal channel, but they differed in water renewal regime. Multidimensional Scaling (MDS) and Discriminant Analysis were used to evaluate the similarity among sites, stations and sampling occasions. Different levels of taxonomic resolution (family, large taxonomic groups and phylum level) were also evaluated. The separation of sites and stations became unclear using high taxonomic levels. Results from the multivariate analyses suggest a slight differentiation of the stations according to sampling occasion but a clear differentiation of the several water reservoirs. Some of the lagoons studied with low water renewal rates showed strong environmental variations. They were characterised by low diversity indexes and abundance of small-sized organisms. Other lagoons, with high water renewal rates, showed low environmental variation and well diversified and structured benthic communities. The main environmental factor that seems to affect the benthic communities was the variation in salinity between neap and spring tides, which is related with the water renewal regime. Coastal lagoons offer a protected shallow habitat, which can be highly productive. Well structured communities, controlled by k-strategists, can develop and settle in leaky lagoons, that is, lagoons with wide entrance channels and tidal currents which guarantee a good water renewal. In these lagoons, biomass can accumulate in large organisms. In contrast, lagoons with a single narrow entrance, that may be closed for long periods, are characterised by persistent physical stress and are dominated by communities of small-sized r-strategists

Integrated multi-trophic aquaculture systems: energy transfers and food web organization in coastal earthen ponds

Three Ecopath models were built to reproduce 3 experimental treatments carried out in earthen ponds located in Olhao, southern Portugal, to understand the energy transferred and the ecosystem state in integrated multi-trophic aquaculture (IMTA). These earthen ponds behave as simplified ecosystems or mesocosms, with well-defined borders, where the relationships between trophic groups can be described through ecosystem modeling. Different combinations of species were produced in these ponds, corresponding to the 3 treatments: (1) fish, oysters and macroalgae (FOM); (2) fish and oysters (FO); and (3) fish and macroalgae (FM). The managed species were meagre Argyrosomus regius, white seabream Diplodus sargus, flathead grey mullet Mugil cephalus, Japanese oyster Crassostrea gigas and sea lettuce Ultra spp. The results showed that the total amount of energy throughput was 15 to 17 times higher when compared with an equivalent naturalized system. The high biomass and low recycling indicated an immature system with low resilience and low stability that demands high rates of water renewal and aeration to maintain good water-quality levels for finfish production. The addition of oysters and macroalgae in the FOM treatment appeared to improve the water quality, since oysters controlled the excess of phytoplankton produced in the ponds by ingesting a fair amount of the phytoplankton, while the macroalgae helped in the absorption of excess nutrients and created a habitat for periphyton and associated macroinvertebrates. Some ecosystem attributes of the FOM ponds approached the values of the naturalized model, suggesting a possible path towards more sustainable aquaculture.COFASP/0003/2015 Interreg Atlantic Area project INTEGRATE EAPA_232/2016 project DIVERSIAQUA Mar2020 16-02-01-FMP-0066 UID/Multi/04326/2019/UID/Multi/04326/2020info:eu-repo/semantics/publishedVersio

Modelling 3D scanned data to visualise and analyse the Built Environment for regeneration

The renovation and refurbishment market is rapidly expanding in the construction industry. The regeneration and transformation of cities from the industrial age (unsustainable) to the knowledge age (sustainable) is essentially a "whole life cycle" process consisting of: planning, development, operation, reuse and renewal. Advanced digital mapping technologies are enablers for effective eplanning, consultation and communication of users' views during the planning, design, construction and lifecycle process of the built environment. Those technologies can be used to drive the productivity gains by promoting a free-flow of information between departments, divisions, offices, and sites; and between themselves, their contractors and partners. Such is the case of the 3D laser scanner which enables digital documentation of buildings, sites and physical objects for reconstruction and restoration. It also facilitates the creation of educational resources within the built environment, as well as the reconstruction of the built environment. The use of the 3D scanner in combination with the 3D printer provides the transformation of digital data from the captured CAD model back to a physical model at an appropriate scale - reverse prototyping. The use of these technologies is key enablers to the creation of new approaches to the ¿Whole Life Cycle¿ process within the built and human environment for the 21st century. The paper describes the research of a building data integration in the INTELCITIES project undertaken by a European consortium of researchers and practitioners under the Framework 6 research programme to develop a prototype system of the e-City Platform in order to pool advanced knowledge and experience of electronic government, planning systems and citizen participation from across Europe (www.intelcitiesproject.com). The scope includes capturing digital data of existing buildings using 3D laser scanning equipment and illustration of how digitised building data can be integrated with other types of city data, using nD modelling, to support integrated intelligent city systems for enhancing the refurbishment process in the built environment

Methodology for assessing the individual role of fish, oyster, phytoplankton and macroalgae in the ecology of integrated production in earthen ponds

Production costs in extensive and semi-intensive fish culture in earthen ponds are often too high to offer sustainable economic activity due to the low productivity of these systems. The right combination of commercial finfish species with inorganic (primary producers) and organic extractive (bivalves) species in Integrated MultiTrophic Aquaculture (IMTA) create a balanced system with higher profitability and risk reduction. To achieve this, it is crucial to understand the role of each functional groups within the system what we did by comparing three different IMTA production three different IMTA production treatments with distinct combinations of trophic levels: •fish, filter feeders, phytoplankton and macroalgae,•fish, filter feeders and phytoplankton•fish, phytoplankton and macroalgae Each treatment was carried out in two similar ponds under semi-intensive conditions and flow through system, in a total of 6 earthen ponds of 500 m2 surface and depth of 1.5 m. Results showed that the presence of oysters in the ponds enhanced water quality by decreasing turbidity and by controlling phytoplankton which led to regulation of dissolved oxygen levels. The enhanced water quality in these systems lead to improved fish performance and higher biomass production contributing to greater profitability. The combination of fish, oyster, phytoplankton and macroalgae was particularly good providing much more fish supply compared with the other two treatments. •Oysters enhanced water quality in the ponds by decreasing turbidity and controlling phytoplankton which regulated the dissolved oxygen levels.•The enhanced water quality in systems with oysters improve fish performance resulting in higher biomass production and greater profitability.•The combination of fish, oyster, phytoplankton and macroalgae was particularly good providing much more fish supply compared with the other two treatments.Funding Agency Fundacao para a Ciencia e a Tecnologia (FCT) COFASP/0003/2015 SFRH/BD/118601/2016 Project DIVERSIAQUA Mar2020 16-02-01-FMP-0066 project Algared+ Poctep 0055_ALGARED_PLUS_5_E UID/Multi/04326/2019info:eu-repo/semantics/publishedVersio