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Biomedical subjects

Sandra Brown

Publications and source records attributed to Sandra Brown.

8 recordsLinked to original sources
PubMed2006

A new locus for autosomal dominant cataract on chromosome 19: linkage analyses and screening of candidate genes.

PURPOSE: To map and identify the mutated gene for autosomal dominant cataract (ADC) in family ADC4. METHODS: Ophthalmic evaluations were performed on an American family with ADC and a panel of polymorphic DNA sequence-tagged site (STS) markers for known ADC loci and other genome-wide polymorphic markers were used to map the gene; two-point lod scores were calculated. Fine mapping was undertaken in the chromosomal regions of maximum lod scores, and candidate genes were sequenced. RESULTS: A four-generation American family with ADC was studied. The only phakic individual exhibited white and vacuolated opacities in the cortical region. This ADC locus mapped to several suggestive chromosomal regions. Assuming full penetrance, the highest calculated maximum lod score was 3.91 with D19S903 [corrected] On chromosome 12, we sequenced all exons and the exon-intron borders of the membrane intrinsic protein (MIP) gene. On chromosome 19, all exons and the exon-intron borders of genes for lens intrinsic membrane2 (LIM2), ferritin light chain (FTL), and the human homologue of the Drosophila sine oculis homeobox 5 (SIX5) were sequenced, and the 3' untranslated repeat region (UTR) of the dystrophy (DMPK) gene and both the 5' and 3' UTRs of the SIX5 genes were amplified; the promoter for LIM2 was sequenced. For these genes, the sequence matched that in the reference libraries, and the DMPK gene had a normal number of CTG repeats. CONCLUSIONS: The mutated gene in ADC4 probably represents a new, not yet identified locus on chromosome 19. In one phakic member, the cortical cataracts were punctate and vacuolated.

Cataract↗
PubMed2006

Circle of strength.

In 1984, the college of nursing at the University of Saskatchewan (U of S), the First Nations University of Canada and the University of Regina, with funding from Health Canada, established the National Native Access Program to Nursing (NNAPN). This program promoted nursing to aboriginal people, negotiated access seats for aboriginal students at all Canadian universities and offered a nine-week spring orientation program intended to prepare aboriginal students for the demands of campus life and nursing programs. A restructuring of the program in 1997 made it provincial in scope, becoming NAPN, which focuses on the recruitment, support and retention of aboriginal nursing students at the U of S's Nursing Education Program of Saskatchewan (NEPS). Currently, more than 200 self-identified aboriginal students are enrolled in NEPS. All aboriginal students are encouraged to access the NAPN services and to become involved in NAPN activities. NAPN advisers strive for success and excellence for aboriginal nursing students through support and advocacy (personal issues, social services, individual funding, academic assistance, advocacy with faculty), summer employment assistance, recruitment efforts and community partnerships (including community-building activities among the students and building partnerships with outside stakeholders, both First Nations and non-First Nations).

Attitude of Health Personnel↗
PubMed2002

Forests, carbon and global climate.

This review places into context the role that forest ecosystems play in the global carbon cycle, and their potential interactions with climate change. We first examine the natural, preindustrial carbon cycle. Every year forest gross photosynthesis cycles approximately one-twelfth of the atmospheric stock of carbon dioxide, accounting for 50% of terrestrial photosynthesis. This cycling has remained almost constant since the end of the last ice age, but since the Industrial Revolution it has undergone substantial disruption as a result of the injection of 480 PgC into the atmosphere through fossil-fuel combustion and land-use change, including forest clearance. In the second part of this paper we review this 'carbon disruption', and its impact on the oceans, atmosphere and biosphere. Tropical deforestation is resulting in a release of 1.7 PgC yr(-1) into the atmosphere. However, there is also strong evidence for a 'sink' for carbon in natural vegetation (carbon absorption), which can be explained partly by the regrowth of forests on abandoned lands, and partly by a global change factor, the most likely cause being 'fertilization' resulting from the increase in atmospheric CO(2). In the 1990s this biosphere sink was estimated to be sequestering 3.2 PgC yr(-1) and is likely to have substantial effects on the dynamics, structure and biodiversity of all forests. Finally, we examine the potential for forest protection and afforestation to mitigate climate change. An extensive global carbon sequestration programme has the potential to make a particularly significant contribution to controlling the rise in CO2 emissions in the next few decades. In the course of the whole century, however, even the maximum amount of carbon that could be sequestered will be dwarfed by the magnitude of (projected) fossil-fuel emissions. Forest carbon sequestration should only be viewed as a component of a mitigation strategy, not as a substitute for the changes in energy supply, use and technology that will be required if atmospheric CO(2) concentrations are to be stabilized.

Air Pollution↗
PubMed2002

Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol.

The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means to absorb or reduce emissions of CO(2) (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions, and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social, environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals.

Air Pollutants↗
PubMed2002

Potential carbon mitigation and income in developing countries from changes in use and management of agricultural and forest lands.

The many opportunities for mitigating atmospheric carbon emissions in developing countries include reforesting degraded lands, implementing sustainable agricultural practices on existing lands and slowing tropical deforestation. This analysis shows that over the next 10 years, 48 major tropical and subtropical developing countries have the potential to reduce the atmospheric carbon burden by about 2.3 billion tonnes of carbon. Given a central price of $10 per tonne of carbon and a discount rate of 3%, this mitigation would generate a net present value of about $16.8 billion collectively for these countries. Achieving these potentials would require a significant global effort, covering more than 50 million hectares of land, to implement carbon-friendly practices in agriculture, forest and previously forested lands. These estimates of host-country income potentials do not consider that outside financial investment may or may not be available. Our calculations take no account of the additional benefits of carbon sequestration in forest soils undergoing reforestation, increased use of biomass and reduced use of fossil-fuel inputs and reduced agricultural emissions. In all events, realizing these incomes would necessitate substantially greater policy support and investment in sustainable land uses than is currently the case.

Africa↗
PubMed2002

Measuring, monitoring, and verification of carbon benefits for forest-based projects.

Worldwide, there are many pilot forestry projects that are under some stage of implementation, and much experience has been gained from them with respect to measuring, monitoring, and accounting for their carbon benefits. Forestry projects have been shown to be easier to quantify and monitor than national inventories, partly because not all pools need measuring: a selective accounting system can be used that must include all pools expected to decrease and a choice of pools expected to increase as a result of the project. Only pools that are based on field measurements should be incorporated into the calculation of carbon benefits. Such a system allows for trade-offs between expected carbon benefits, costs, and desired precision, while maintaining the integrity of the net carbon benefits. Techniques and methods for accurately and precisely measuring individual carbon pools in forestry projects exist, are based on peer reviewed principles of forest inventory, soil sampling, and ecological surveys, and have been well tested in many part of the world. Experience with several forestry projects in tropical countries has shown that with the use of these techniques carbon stocks can readily be estimated to be within less than +/-10% of the mean. To date, there is little experience with measuring the changes in carbon stocks over time but, using the correct design and sufficient numbers of permanent plots, it is expected that precision levels will be maintained at less than +/-10% of the mean. Internal verification can be accomplished through use of quality assurance/quality control plans. External or third-party verification is still in its infancy, and would greatly benefit from international agreements in relation to protocols used for all aspects of project design and implementation.

Biomass↗
PubMed2002

Measuring carbon in forests: current status and future challenges.

To accurately and precisely measure the carbon in forests is gaining global attention as countries seek to comply with agreements under the UN Framework Convention on Climate Change. Established methods for measuring carbon in forests exist, and are best based on permanent sample plots laid out in a statistically sound design. Measurements on trees in these plots can be readily converted to aboveground biomass using either biomass expansion factors or allometric regression equations. A compilation of existing root biomass data for upland forests of the world generated a significant regression equation that can be used to predict root biomass based on aboveground biomass only. Methods for measuring coarse dead wood have been tested in many forest types, but the methods could be improved if a non-destructive tool for measuring the density of dead wood was developed. Future measurements of carbon storage in forests may rely more on remote sensing data, and new remote data collection technologies are in development.

Carbon↗