20 research outputs found

    Reconstruction of coded aperture images

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    Balanced correlation method and the Maximum Entropy Method (MEM) were implemented to reconstruct a laboratory X-ray source as imaged by a Uniformly Redundant Array (URA) system. Although the MEM method has advantages over the balanced correlation method, it is computationally time consuming because of the iterative nature of its solution. Massively Parallel Processing, with its parallel array structure is ideally suited for such computations. These preliminary results indicate that it is possible to use the MEM method in future coded-aperture experiments with the help of the MPP

    Environmental and Molecular Mutagenesis Meeting Report Assessing Human Germ-Cell Mutagenesis in the Post-Genome Era: A Celebration of the Legacy of William Lawson (Bill) Russell

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    ABSTRACT Although numerous germ-cell mutagens have been identified in animal model systems, to date, no human germ-cell mutagens have been confirmed. Because the genomic integrity of our germ cells is essential for the continuation of the human species, a resolution of this enduring conundrum is needed. To facilitate such a resolution, we organized a workshop at The Jackson Laboratory in Bar Harbor, Maine on September [28][29][30] 2004. This interactive workshop brought together scientists from a wide range of disciplines to assess the applicability of emerging molecular methods for genomic analysis to the field of human germ-cell mutagenesis. Participants recommended that focused, coordinated human germ-cell mutation studies be conducted in relation to important societal exposures. Because cancer survivors represent a unique cohort with well-defined exposures, there was a consensus that studies should be designed to assess the mutational impact on children born to parents who had received certain types of mutagenic cancer chemotherapy prior to conceiving their children. Within this high-risk cohort, parents and children could be evaluated for inherited changes in (a) gene sequences and chromosomal structure, (b) repeat sequences and minisatellite regions, and (c) global gene expression and chromatin. Participants also recommended studies to examine trans-generational effects in humans involving mechanisms such as changes in imprinting and methylation patterns, expansion of nucleotide repeats, or induction of mitochondrial DNA mutations. Workshop participants advocated establishment of a bio-bank of human tissue samples that could be used to conduct a multiple-endpoint, comprehensive, and collaborative effort to detect exposure-induced heritable alterations in the human genome. Appropriate animal models of human germ-cell mutagenesis should be used in parallel with human studies to provide insights into the mechanisms of mammalian germ-cell mutagenesis. Finally, participants recommended that 4 scientific specialty groups be convened to address specific questions regarding the potential germ-cell mutagenicity of environmental, occupational, and lifestyle exposures. Strong support from relevant funding agencies and engagement of scientists outside the fields of genomics and germ-cell mutagenesis will be required to launch a full-scale assault on some of the most pressing and enduring questions in environmental mutagenesis: Do human germ-cell mutagens exist, what risk do they pose to future generations, and are some parents at higher risk than others for acquiring and transmitting germ-cell mutations?

    Helios is a key transcriptional regulator of outer hair cell maturation

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    The sensory cells that are responsible for hearing include the cochlear inner hair cells (IHCs) and outer hair cells (OHCs), with the OHCs being necessary for sound sensitivity and tuning1. Both cell types are thought to arise from common progenitors; however, our understanding of the factors that control the fate of IHCs and OHCs remains limited. Here we identify Ikzf2 (which encodes Helios) as an essential transcription factor in mice that is required for OHC functional maturation and hearing. Helios is expressed in postnatal mouse OHCs, and in the cello mouse model a point mutation in Ikzf2 causes early-onset sensorineural hearing loss. Ikzf2cello/cello OHCs have greatly reduced prestin-dependent electromotile activity, a hallmark of OHC functional maturation, and show reduced levels of crucial OHC-expressed genes such as Slc26a5 (which encodes prestin) and Ocm. Moreover, we show that ectopic expression of Ikzf2 in IHCs: induces the expression of OHC-specific genes; reduces the expression of canonical IHC genes; and confers electromotility to IHCs, demonstrating that Ikzf2 can partially shift the IHC transcriptome towards an OHC-like identity

    Deficit discourse – the ‘regime of truth’ preceding the Cape York Welfare Reform

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    The Cape York Welfare Reform (CYWR) income management regime commenced in 2008. While this regime was supported and funded by the Queensland and federal governments, it was essentially developed by the Cape York Institute for Policy and Leadership (CYI), which was known as an Aboriginal policy development think tank. Income management in Cape York involves quarantining between 60% and 90% of a person's social security payment, if the person is deemed to have breached particular social responsibilities. The decision to income manage social security payments of CYWR community members, was based on a belief and writings by the CYI that there was a social norms deficit in Cape York communities, which income management could play a role in addressing. The language used by the CYI to describe Cape York community life was negative in the extreme, dramatic and evocative. This language, which I describe as deficit discourse, commanded a response to what was described as a dire situation. This article frames this deficit discourse in the broader and continuing context of colonisation. This discourse has been applied consistently throughout Australia's colonial history, perpetuating racial discrimination and justifying continuous governmental intervention into Aboriginal and Torres Strait Islander people's lives

    Fifty-nine microsatellite markers for hybrid classification studies involving endemic Florida Mottled Duck (Anas fulvigula fulvigula) and invasive Mallards (A. platyrhynchos)

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    Endemic Florida Mottled Duck (Anas fulvigula fulvigula) appear to be hybridizing introgressively with domesticated Mallards (A. platyrhynchos), which are frequently released or escape captivity and have established feral populations throughout Florida. To investigate this possible conservation threat, we isolated and characterized 59 polymorphic loci from an enriched Florida Mottled Duck microsatellite library and performed cross-amplification assays with Mallard specimens. Average numbers of alleles per locus were 6.0 (ranging 2-23) and 5.6 (ranging 2-15) for A. fulvigula and A. platyrhynchos, respectively; estimates of observed/expected heterozygosity were 0.54/0.63 and 0.52/0.64. Markers developed in this study will be used in conjunction with existing markers to robustly classify hybrids and to assess and monitor the genetic dynamics of introgression between these waterfowl species
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