Assessment of classical database models for representing solids

Solid modeling is being explored as a method of representing three dimensional parts for mechanical design and manufacturing. This work analyzes the data storage requirements of the Boundary Representation and Constructive Solid Geometry methods of representing solid models. The ability of the database models (Hierarchical, Network, and Relational) to support solid modeling needs is evaluated. The goal is to determine the database model(s) best suited to store and manage the graphical data for solid model representat ions . Background information about mechanical engineering, graphics, and database models is presented. Entity-Relationship diagrams are used to define data requ irements

Implementation of a proprietary CAD graphics subsystem using the GKS standard interface.

Thesis (M.Sc.)-University of Natal, Durban, 1989.This project involved porting a Graphical Software Package (GSP) from the proprietary IDS-BO Gerber CAD system onto a more modern computer that would allow student access for further study and development. Because of the popularity of Unix as an "open systems environment", the computer chosen was an HP9000 using the HP-UX operating system. In addition, it was decided to implement a standard Graphical Kernel System (GKS) interface to provide further portability and to cater for the expected growth of the GKS as an international standard. By way of introduction, a brief general overview of computer graphics, some of the essential considerations for the design of a graphics package and a description of the work undertaken are presented. Then follows a detailed presentation of the two systems central to this project i) the lDS-8O Gerber proprietary CAD system, with particular attention being paid to the Graphical Software Package (GSP) which it uses and ii) the Graphical Kernel System (GKS) which has become a widely accepted international graphics standard. The major differences between the lDS-8O Gerber GSP system and the GKS system are indicated. Following the theoretical presentation of the GSP and GKS systems, the practical work involved in first implementing a "skeleton" GKS interface on the HP9000 Unix System, incorporating the existing Advanced Graphics Package (AGP) is presented. The establishment of a GKS interface then allows an lDS-8O Gerber GSP interface to be developed and mapped onto this. Detailed description is given of the methods employed for this implementation and the reasons for the data structures chosen. The procedures and considerations for the testing and verification of the total .system implemented on the HP9000 then follow. Original lDS-8O Gerber 2-D .applications software was used for the purpose of testing. The implementation of the data base that this software uses is also presented. Conclusions on system performance are finally presented as well as suggested areas for possible further work

Ecological features, populations traits and conservation status of Helianthemum caput-felis along its distribution range

Understanding factors limiting populations’ growth and persistence is crucial to evaluate the current conservation status and possible future management of plant populations. This Ph.D. thesis focussed on ecological constraints related to population trends and the conservation status of Helianthemum caput-felis Boiss., characterized by a highly fragmented areal isolated from the distribution centre. In particular, the specifics aims of the thesis were: (1) to analyse the distribution range, population size, the reproductive traits, the effect of human disturbance and identify the threats affecting the persistence of H. caput-felis in Sardinia following the IUCN regional protocol; (2) to investigate flowers and fruits phenology, ecological traits (geomorphology, substrate, slope and human trampling intensity) affecting reproductive outputs (as fruit and seed sets) and the presence of two ecological gradients along the entire European distribution range of the species; (3) to discover the population dynamics by the analyses of populations vital rates, both at global level than a local scale; (4) to evaluate the risk of extinction of H. caput-felis at global level, and then to assess the global conservation status of the populations, together with an accurate analysis of the global area of occupancy of the species, following the IUCN protocol. The thesis results indicate relevant aspect regarding the ecology, population dynamics, distribution and conservation traits of the species. In Sardinia, the species preferably grows in lowland areas with deep structured soil, due to the amount of water and resources available and morphological stability. H. caput-felis shows the highest reproductive output in garrigues, habitat that represents its ecologically optimum. The high seed production indicates that this is not a limiting factor for this plant, in contrast to seedling establishment, which represent its main critical stage. Surprisingly, in Sardinia, human trampling enhanced the plant size and the rate of fruits production, suggesting that reproductive plants of H. caput-felis are tolerant to direct damage, and probably benefit from the reduction of inter-specific and intra-specific competition. Comparing the phenology and reproductive output along the entire European distribution range of this species over a two year temporal context indicate that the general phenological pattern of H. caput-felis was similar among Sardinian and Majorcan regions, whereas, in the eastern Iberian populations (the western part of the distribution range), the southern population (Cabo Roig) showed a higher inter-annual variability and an early flowering period. Those differences could be related to a longitudinal aridity gradient for this plant: the aridity decreases from western to eastern localities. Plants growing at the eastern edge of the distribution range (Sardinia) produce more viable fruits, fruits per plant and seeds per fruit than the other two regions, while plants growing in arid substrate (as in the sandy habitat of Sa Ràpita, Majorca) are the least productive, confirming that sandy substrate is negatively correlated with fruits production and viable fruits, as well as lowland geomorphology. Hence, these analyses underline that the Abundant Centre Model assumptions, by which reproductive traits should be higher at the centre of species distribution, is not confirmed for H. caput-felis, maybe because the central populations, represented by the largest distribution area along the Iberian’s coasts, appear strongly fragmented mainly by human disturbance. Demographic traits of H. caput-felis population were analysed, by using demographic surveys, integrated by Matrix and Integral Projection Models (MPM and IPM, respectively). Plant performance and population dynamics were investigated in plants sampled along the comprehensive and representative part of the European distribution range in which the species occurs. The global population showed a general stability in the first year transition, after which it declined. This trend was probably due to the higher shrinkage of plants in the last year of study, which correlates negatively with reproductive traits, in agreement with the frequent increase in reproductive outputs with plant size. Despite this decline, stochastic population growth rate highlighted as H. caput-felis population oscillated around the equilibrium. Elasticity analysis indicated the higher importance of large individuals and the determinant role of the survival-growth transitions for the population growth rate. Moreover, plants reached high generation times and mean long life span, which, with the limited seedling recruitment rate and the presence of a consistent seed bank, reflect patterns that are typical both of many long-lived plants and of calcareous rupicolous Mediterranean species. IPM methods were found to be more accurate than MPM to monitoring species with restricted range, as H. caput-felis. At local level, the pattern of typical long-lived Mediterranean plants was also confirmed; in fact, populations were mainly composed from large individuals, characterized by slow growth. H. caput-felis showed vital rates and population dynamics varying among populations: the Sardinians’ seems to have greater equilibrium than Spanish populations. The high population growth rates of Moraira and Colònia de Sant Jordi were strongly influenced by the fecundity parameters. Plants growing in Moraira show a uniform shrinkage of individuals, probably due to a more intense fragmentation of the population. The different population dynamics observed among the analysed localities of H. caput-felis should be correlated to particular microclimate and ecological conditions, i.e. the high aridity of Cabo Roig and the sand substrate of Sa Ràpita, which probably affected the relationship among size and vital rates. On the contrary, H. caput-felis populations in demographic equilibrium, as the Sardinians’, could be locally adapted to ecological and microclimate conditions. Finally, population dynamics models were applied to analyse the extinction risk and then assess the global conservation status of H. caput-felis, together with an accurate analysis of the global area of occupancy of the species, following the IUCN protocol. This research highlighted that H. caput-felis should be considered an Endangered (EN) plant at global level, according to the formula B2ab (ii,iii,iv,v) + E. H. caput-felis suffered a continuing decline in AOO, quality of its habitat, number of localities and number of reproductive plants. This decline rate was mainly due to the habitat loss and the expansion of infrastructures detected in the last decades. Hence, effective future conservation measures could be focussed on protecting the single localities where H. caput-felis grows, in order to avoid further species decline. In this contest, conservation efforts primarily aimed to protect established individuals (mature plants) against disturbances, as suggested for other long-lived species. The results of this thesis gave new findings for the ecology and conservation of H. caput-felis, and demonstrate the importance to considerate both global than local level in demography and phenology studies

Standards and innovations: university computer labs and the Market Reserve in Brazil

El objetivo de este artículo es analizar la producción de uno de los laboratorios de la Escuela Politécnica de la Universidad de São Paulo, el Laboratorio de Sistemas Integrados (LSI), entre 1970 y 1980. La investigación evaluó tesis, disertaciones y proyectos desarrollados en orden comprender cómo los temas de innovación y desarrollo tecnológico en la producción de artefactos en un entorno académico. Buscamos dilucidar posibles tensiones en el uso de equipos que deben seguir los estándares disponibles en el mercado interno, en un momento en que en Brasil se estaba llevando a cabo el control de las importaciones de insumos informáticos, conocido como Reserva de Mercado. El desarrollo de propuestas de adaptación tecnológica fue la respuesta nacional de la ingeniería a esa situación derivada de la política brasileña de tecnologías de la información.The aim of this article is to analyze the production of one of the laboratories of the Polytechnic School of the University of São Paulo, the Integrated Systems Laboratory (LSI), between 1970 and 1980. The research evaluated theses, dissertations, and projects developed to understand how the themes of innovation and technological development were handled in the production of artifacts in an academic environment. We sought to elucidate possible tensions in the use of equipment that should follow the standards available in the domestic market while the control of imports of computer inputs, known as Market Reserve, was taking place in Brazil. The development of proposals for technological adaptation was the response of national engineering to that situation arising from the Brazilian information technology policy.Sociedad Argentina de Informática e Investigación Operativ

A preliminary global red list assessment of selected crop wild relatives: conservation status, analysis and implications

Crop wild relatives (CWR) are valuable socio-economic resources that provide a genetic reservoir of potential adaptability for our food crops. Despite their importance, these vital resources are in dire need of sustainable and strategic conservation. The IUCN Red List Categories and Criteria are the world’s most widely accepted methodology for assessing species’ risk of extinction, and was applied to a selection of priority CWR extracted from the Harlan and de Wet CWR Inventory (Vincent et al., 2013). Preliminary results show that, seventeen CWR species (6.3%) were found to be threatened with extinction, with 0.7% (two species) being Critically Endangered (CR), 3.4% (nine species) being Endangered (EN), and 2.2% (six species) being Vulnerable (VU). In addition to this, 60.7% of CWR species studied were found to be LC, and a further 29.6% were deemed DD. Threatened species were considered highest priority for conservation efforts, while monitoring and management of those species for which population is in decline is also important regardless of threat category. While the current project presents valuable insight, expansion of this to a larger, more representative sample of priority CWR species is advised. Further analysis highlighted the lack of data available for CWR in general and more specifically concerning population information such as size, status and trends; further research to increase the knowledge base for CWR is vital in securing the complementary and strategic conservation of these resources and future food security

Merger Dynamics and Stellar Populations in the Host Galaxies of the Quasi-Stellar Objects I Zw 1 and 3C 48

The thesis focuses on two case studies of the host galaxies of the quasi-stellar objects (QSOs) I Zw 1 and 3C 48. The studies are motivated by the hypothesis that ultra-luminous infrared galaxies (ULIRGs) might represent the early stage of QSO evolution (Sanders et al. 1988). According to this hypothesis, galaxy mergers and interactions trigger gas inflow which is followed by starburst activity and by the formation of an active nucleus. As likely transitionary objects between the ultra-luminous infrared stage and the QSO stage, I Zw 1 and 3C 48 are promising candidates to investigate the active nucleus, the starburst, and the merger properties as the essential links between all stages of the proposed evolutionary sequence. The case study of I Zw 1 has an observational focus and is based on near-infrared (NIR) imaging and spectroscopy, carried out with ISAAC (Infrared Spectrometer and Array Camera) at the Very Large Telescope of the European Southern Observatory (ESO) on Cerro Paranal in Chile. The two-armed spiral host galaxy of I Zw 1 shows two bright knots in the north and in the west of the optical disk region, respectively. Here, the new ISAAC spectra indicate that the northern object is a projected foreground star, as previously assumed but recently challenged. In the surroundings of the western source, the ISAAC J-band image displays tidal features. This gives further support for the scenario that I Zw 1 is presently in a minor merger process with this source. The new spectra and the NIR colors of the western source indicate an old stellar population. The host of I Zw 1 is analyzed in a one-dimensional structural decomposition into bulge, disk, and halo components, which results in mean J-band mass-to-light ratios. The latter indicate a young mean stellar population in the bulge component, while the disk ratios agree with those of normal spiral galaxies. Such a scenario of younger stellar populations in the central region of the I Zw 1 host is also plausible from a two-color analysis. The nuclear ISAAC spectrum of I Zw 1 basically confirms previous results, by showing hydrogen emission lines and indications of extremely blueshifted high-excitation lines. The case study of 3C 48 is the numerical focus of this thesis and based on simulations with multi-particle methods. The aim is to investigate the major merger scenario for 3C 48 by reproducing a 3C 48 model. Such a model is found for a certain projection angle during the inclined merger of two equal-mass spiral galaxies. It inspirits a new idea for the problem of the apparently missing second tidal tail in 3C 48. For the derived projection angle, this tidal tail is located in front of the main body of the modeled host galaxy and is likely to be missed in observations. In the model, both galaxy centers are still separated. This leaves room to interpret the known second luminosity peak, north-east of the QSO in 3C 48, as the center of the galaxy merging with 3C 48. A central gas accumulation and a complex system of gas lanes develop in the simulation with a non-gravitating gas component added. Both results qualitatively agree with the known distribution of molecular gas in 3C 48. The new results about I Zw 1 and 3C 48 complement the existing assumption that both are likely transitionary objects in the evolutionary sequence

COBE's search for structure in the Big Bang

The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle

Biodiversity messaging to generation Y students at the Durban University of Technology, KwaZulu-Natal.

Doctor of Philosophy in Centre for Communication, Media and Society. University of KwaZulu-Natal, Durban 2016.This study deals with the intersection of three global influences that are rapidly changing our world; the first a looming environmental crisis or loss of biodiversity, the second the growing influence of a new generation of students (Generation Y) who possess the ability and power to reshape the socio political, economic and cultural landscape and finally the phenomenal power and penetration of multimedia communication platforms. Mindful of these global themes and context this particular research focuses on a relatively new area of study not yet covered in the literature, that of South African university students perceptions of nature. The study involved establishing the extent of the knowledge, attitudes and perceptions of South African students (Generation Y) toward Nature, discovering how they connect with local biodiversity and determining the best communication modes for reaching this audience. The work posited that Generation Y students may be unfamiliar with the exact meaning and significance of the term biodiversity but could respond positively when exposed to nature based experiences at accessible botanic gardens, and protected urban green spaces. Student opinions (n= 428) at the Durban University of Technology were sampled statistically using an appropriate survey instrument. The resultant quantitative data revealed significant student levels of concern for biodiversity loss and a strong cultural bias in terms of personal linkages with medicinal plants. Visitor frequency to nature reserves was low however the use of botanic gardens proved more popular. Visual modes of communication such as television were preferred over text modalities and while the influence of multimedia electronic platforms was acknowledged the possible use of nature apps received a limited response. Qualitative data gathered from four focus groups involved guided discussion on the relevance of biodiversity, and local field visits to Pigeon Valley Nature Reserve and the Durban Botanic Gardens. Students produced response posters which revealed high levels of personal empathy and connection to nature, emphasizing existing cultural connections with local plants. A biodiversity communication model for South African university students was presented building on these findings

Finite elements software and applications

The contents of this thesis are a detailed study of the software for the finite element method. In the text, the finite element method is introduced from both the engineering and mathematical points of view. The computer implementation of the method is explained with samples of mainframe, mini- and micro-computer implementations. A solution is presented for the problem of limited stack size for both mini- and micro-computers which possess stack architecture. Several finite element programs are presented. Special purpose programs to solve problems in structural analysis and groundwater flow are discussed. However, an efficient easy-to-use finite element program for general two-dimensional problems is presented. Several problems in groundwater flow are considered that include steady, unsteady flows in different types of aquifers. Different cases of sinks and sources in the flow domain are also considered. The performance of finite element methods is studied for the chosen problems by comparing the numerical solutions of test problems with analytical solutions (if they exist) or with solutions obtained by other numerical methods. The polynomial refinement of the finite elements is studied for the presented problems in order to offer some evidence as to which finite element simulation is best to use under a variety of circumstances

Unraveling bacterioplanktonic ecology of the estuaries of Urdaibai and Bilbao in the Bay of Biscay by high-throughput sequencing

244 p.Planktonic communities are widely used as indicators of water pollution level, as they are vulnerableto water quality status. Indeed, it has been proposed that estuaries microbial composition changesduring eutrophication period due to the increase of pollutants and hypoxia. In the present study, wecharacterized the bacterial community structure of two macro-mesotidal estuaries by sequencing theV4 region of the 16s rDNA gene. While Bilbao estuary crosses a densely populated urban area, theUrdaibai estuary is an UNESCO biosphere reserve. Results evidenced that the bacterial speciescomposition and abundance of both estuaries significantly differed between the inner and outer watermasses. Moreover, seasonal effects on community structure were detectable in the inner zones of bothestuaries, but only minor variation were found in the outer waters, presumably due to a more stablephysicochemical environment common in open sea waters. In fact, community structure significantlydiffered in this period, suggesting a low turnover time for inner water mass in this estuary. Moreover,it has been observed that the bacterial metabolism is different in each of water mass, especially in themass of eutrophic water and in the waters around the WWTP of Bilbao