Evaluation of a commercially available rapid urinary porphobilinogen test

Background: Demonstration of substantially increased urinary excretion of porphobilinogen is the cornerstone of diagnosing acute porphyria crisis. Because porphobilinogen testing is not implemented on clinical chemistry analysers, respective analyses are available in rather few clinical laboratories. The aim of this study was to critically describe and to evaluate a semi-quantitative rapid test for urinary porphobilinogen determination which is commercially available and recommended by the American Porphyria Foundation. Methods: Urinary samples from patients with acute intermittent porphyria and control samples were analysed and the semi-quantitative results were compared with the results obtained by a manual quantitative spectrophotometric method. Results: In all 32 samples studied, acceptable agreement between the results of the rapid test and the quantitative test was observed. Handling of the test was found to be convenient. Conclusions: The assay was found to be reliable and has the potential to increase the availability of porphobilinogen testing in the field

Highway Sizing

A critical examination is made of the conventional method for highway sizing, that is, determination of lane requirements. Ranked hourly traffic volume distributions, obtained from 1977 Kentucky volume stations are examined to test certain assumptions common to the conventional approach. Several of these distributions have no distinct knee and, for those which do, the knee is most frequently found outside the normally anticipated range. Of equal importance, the knee location can be arbitrarily altered simply by changing the number of highest volume hours that are examining. The fundamental fallacy of the conventional procedure is its focus on a single design hour and its orientation toward conditions experienced by the the highway rather than the user. This can readily be overcome by basing size decisions on an alternate criterion such as the percentage of vehicles that suffer congestion during the design life. An example demonstrating this concept is presented. More significant improvement can be achieved by directly computing the economic efficiency of investment in additional lanes. An example is presented to demonstrate current capabilities for such computations. the example also demonstrates that current procedures do not always yield the mos economical designs and that the most economical highway size is affected by the specific shape of the traffic volume distribution. Use of economic efficiency analysis as a standard tool in evaluating critical sizing decisions is highly recommended

Giraffe translocation population viability analysis

Most populations of giraffes have declined in recent decades, leading to the recent IUCN decision to upgrade the species to Vulnerable status, and some subspecies to Endangered. Translocations have been used as a conservation tool to re-introduce giraffes to previously occupied areas or establish new populations, but guidelines for founding populations are lacking. To provide general guidelines for translocation projects regarding feasibility, we simulated various scenarios of translocated giraffe populations to identify viable age and sex distributions of founding populations using population viability analysis (PVA) implemented in Vortex software. We explored the parameter space for demography and the genetic load, examining how variation in founding numbers and sex ratios affected 100 yr probability of population extinction and genetic diversity. We found that even very small numbers of founders (N ≤ 10 females) can appear to be successful in the first decades due to transient positive population growth, but with moderate population growth rate and moderate genetic load, long-term population viability (probability of extinction 95% genetic diversity of the source population in an isolated population, 50 females and 5 males are recommended to compose the founding population. Sensitivity analyses revealed first-year survival and reproductive rate were the simulation parameters with the greatest proportional influence on probability of extinction and genetic diversity. These simulations highlight important considerations for translocation success and data gaps including true genetic load in wild giraffe populations

Elementary School Leaders’ Perspectives on LGBTQ Inclusive Literacy Instruction K-6: A Quantitative Study

Students in American schools who are or are perceived to be lesbian, gay, bisexual, transgender, and queer (LGBTQ) represent an historically disenfranchised group. They report experiencing bullying and harassment due to their sexual orientation or gender expression or both. Also, LGBTQ students report not having access to curriculum that is inclusive of LGBTQ representations. Elementary students deserve to read texts in which they see themselves in the books they read (mirrors) and have a glimpse into the lives of people that are unlike them (windows). Elementary school administrators, as the instructional leaders of their buildings, are in a critical position to ensure students have access to literacy instruction that is inclusive of individuals who are LGBTQ. This quantitative study sought to determine if a correlation existed between elementary school administrators’ beliefs and levels of comfort in leading LGBTQ inclusive literacy instruction, their perceptions of the barriers that impede leadership in this area, their actions and behaviors that support change for this group, and their sense of urgency in leading LGBTQ inclusive literacy instruction at the elementary level. Furthermore, the study sought to reveal if there were statistically significant differences between groups based on demographic variables of school leaders and characteristics of their schools and administrators’ beliefs and levels of comfort, perceived barriers, actions and behaviors, and sense of urgency in leading LGBTQ inclusive literacy instruction at the elementary level

Threshold between land and sea : new waterborne transport node for the City of Maputo

The chosen project stems from the broader context of Maputo as waterfront city. Increased industrial privatisation of the harbour strip adjacent to the city’s historic Baixa district led to the relocation of public functions, away from the downtown water’s edge and so disconnecting city life from the water. The potential of the city reconnecting to the water is thus latent. The dissertation responds to this potential by reintroducing a public program to the waterfront site. The building integrates with a greater urban vision for the precinct, whereby the industrial waterfront strip is reprogrammed with a layer of mixed use functions. A water-borne public transport node is the architectural typology to be explored. The architectural study aims to investigate the consolidation of currently fragmented water transport modes in one facility and so promote integration between different users and the public. Exploration also includes investigation of dualities and contrasts. Interaction between formal and informal trade, water and land transport, and international trends versus local influences are explored. The projected growth of the city further necessitates the expansion and improvement of water transport infrastructure. The proposed interchange connects all public water -borne modes of transport in Maputo, additionally establishing the link between the city and the water, and subsequently the downtown area with satellite suburbs around Maputo Bay. The design acknowledges the historic nature of the site and context, and adds an additional layer whilst responding to the richness of the existing in an environmentally sensitive manner. The social context of Maputo as a capital city in a developing country is another important consideration. The informal, public, transient nature of the context informs the design, juxtaposed against a first world, international business and tourism centre. The facility will aid in the reintegration of the waterfront with the city, effectively connecting it to other modes of transport.Dissertation (MArch(Prof))--University of Pretoria, 2011.Architectureunrestricte

Structure Prediction of Perovskite Surfaces and Nanoclusters

Perovskite materials possess a broad range of novel and useful properties. This has lead to perovskites being used in a broad range of applications, with considerable ongoing research being invested into them. While the bulk structure of these materials have been thoroughly investigated and documented, the polar surface and nanocluster structures of these compounds are relatively unknown. This is largely due to conventional structural determination techniques, such as X-ray and neutron scattering, proving ine ective on these non-bulk phases. In this thesis computational methods have been used to model the ABZ3 type perovskite materials KTaO3, KMgF3, and KZnF3. Global optimisation techniques have been employed to predict the structure of the compounds in non-bulk phases. The global optimisations were performed using interatomic potentials, with the lowest energy candidates being re ned through density functional theory. Reconstructions of the (001) polar KTaO3 surface were investigated. It was found that the lowest energy reconstructions involved the migration of the Ta ions from the surface, towards the bulk, where they were able to achieve a fuller coordination. The K ions moved in the opposite direction, migrating towards the surface. Defects in the form of neutral K and O vacancies were introduced to the surface. It was found that both types of vacancy resulted in an upward band bending towards the surface. This indicated an accumulation of holes at the surface for K vacancies, and an accumulation of electrons in the bulk for O vacancies. The structures of small nanoclusters, containing 5 - 100 atoms, were predicted for the compounds KMgF3 and KZnF3. The low energy structures revealed that it was energetically favourable for the B cations, Mg or Zn, to adopt positions close to the cluster centre, while the K cations resided at the edges of the clusters. The optical gap of the clusters was found to vary with the size of the cluster. This indicates the properties may be tuned by controlling cluster size

A model of hyphal tip growth involving microtubule-based transport

We propose a simple model for mass transport within a fungal hypha and its subsequent growth. Inspired by the role of microtubule-transported vesicles, we embody the internal dynamics of mass inside a hypha with mutually excluding particles progressing stochastically along a growing one-dimensional lattice. The connection between long range transport of materials for growth, and the resulting extension of the hyphal tip has not previously been addressed in the modelling literature. We derive and analyse mean-field equations for the model and present a phase diagram of its steady state behaviour, which we compare to simulations. We discuss our results in the context of the filamentous fungus, Neurospora crassa.Comment: 5 pages, 5 figure

Global terrestrial distribution of penguins (Spheniscidae) and their conservation by protected areas

Establishing protected areas (PAs) ranks among the top priority actions to mitigate the global scale of modern biodiversity declines. However, the distribution of biodiversity is spatially asymmetric among regions and lineages, and the extent to which PAs offer effective protection for species and ecosystems remains uncertain. Penguins, regarded as prime bioindicator birds of the ecological health of their terrestrial and marine habitats, represent priority targets for such quantitative assessments. Of the world’s 18 penguin species, eleven are undergoing population declines, for which ten are classified as ‘Vulnerable’ or ‘Endangered’. Here, we employ a global-scale dataset to quantify the extent to which their terrestrial breeding areas are currently protected by PAs. Using quantitative methods for spatial ecology, we compare the global distribution of penguin colonies, including range and population size analyses, with the distribution of terrestrial PAs classified by the International Union for Conservation of Nature, and generate hotspot and endemism maps worldwide. Our assessment quantitatively reveals < 40% of the terrestrial range of eleven penguin species is currently protected, and that range size is the significant factor in determining PA protection. We also show that there are seven global hotspots of penguin biodiversity where four or five penguin species breed. We suggest that future penguin conservation initiatives should be implemented based on more comprehensive, quantitative assessments of the multi-dimensional interactions between areas and species to further the effectiveness of PA networks

Advection, diffusion and delivery over a network

Many biological, geophysical and technological systems involve the transport of resource over a network. In this paper we present an algorithm for calculating the exact concentration of resource at any point in space or time, given that the resource in the network is lost or delivered out of the network at a given rate, while being subject to advection and diffusion. We consider the implications of advection, diffusion and delivery for simple models of glucose delivery through a vascular network, and conclude that in certain circumstances, increasing the volume of blood and the number of glucose transporters can actually decrease the total rate of glucose delivery. We also consider the case of empirically determined fungal networks, and analyze the distribution of resource that emerges as such networks grow over time. Fungal growth involves the expansion of fluid filled vessels, which necessarily involves the movement of fluid. In three empirically determined fungal networks we found that the minimum currents consistent with the observed growth would effectively transport resource throughout the network over the time-scale of growth. This suggests that in foraging fungi, the active transport mechanisms observed in the growing tips may not be required for long range transport.Comment: 54 pages including appendix, 10 figure