368 research outputs found

    Butterfly Diversity on a Southeast Florida Military Base Located within an Urban Matrix

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    South Florida is a renowned ‘hotspot’ for rare and endemic taxa, with insects and plants found in few other ecosystems. Specialized species evolved in Florida’s stochastic climate, adapting to seasonal drought and flooding, hurricanes and high-wind tropical storms. As human population growth and development increased, and natural ecosystems disappeared, or became increasingly degraded, at-risk taxa now face additional threats, such as urban pesticide use and fragmented remnant habitats. The ability of species to adapt to these changing ecological factors is one of the dynamics that either impacts their fitness to greater survival or drives extirpation or extinction. Butterflies are native indicator species that can be used to document environmental conditions affecting many other taxa. Butterfly surveys were conducted over 16 months on an active military air reserve base located within a mosaic of densely populated urban, commercial, industrial, residential, and agricultural matrices in Homestead, southeast Florida. Butterfly species richness, abundance and diversity were documented, providing valuable base-line data for on-going butterfly monitoring, and the importance of this site’s relatively healthy remnant ecosystems was evidenced by the supporting host plants for 20 migratory butterflies in 40 species. In addition, the air reserve base acts as refugia for many rare, endangered, and threatened federal and state-listed plants as well.

    Differential utilization of NF-kappaB RELA and RELB in response to extracellular versus intracellular polyIC stimulation in HT1080 cells

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    Abstract Background Pattern recognition receptors (PRRs) for double-stranded RNA (dsRNA) are components of innate immunity that recognize the presence of viral infection and initiate efficient defense mechanisms. In addition to previously well-characterized signaling pathways that are mediated by PKR and TLR3, new intracellular dsRNA sensors, that are members of CARD and DExD/H box helicase family, have been identified. However, the molecular mechanisms involved in the signaling pathways mediated by these new dsRNA sensors have not been extensively characterized. Results Here, we studied an intracellular dsRNA pathway in the human fibrosarcoma cell line HT1080, which is distinct from the TLR3-mediated extracellular dsRNA pathway. Particularly, the NF-kB subunits RELA and RELB were differentially utilized by these two dsRNA signaling pathways. In TLR3-mediated dsRNA signaling, siRNA knock-down studies suggested a limited role for RELA on regulation of interferon beta and other cytokines whereas RELB appeared to have a negative regulatory role. By contrast, intracellular dsRNA signaling was dependent on RELA, but not RELB. Conclusions Our study suggests that extracellular and intracellular dsRNA signaling pathways may utilize different NF-kB members, and particularly the differential utilization of RELB may be a key mechanism for powerful inductions of NF-kB regulated genes in the intracellular dsRNA signaling pathway

    Exploiting the noise: improving biomarkers with ensembles of data analysis methodologies.

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    BackgroundThe advent of personalized medicine requires robust, reproducible biomarkers that indicate which treatment will maximize therapeutic benefit while minimizing side effects and costs. Numerous molecular signatures have been developed over the past decade to fill this need, but their validation and up-take into clinical settings has been poor. Here, we investigate the technical reasons underlying reported failures in biomarker validation for non-small cell lung cancer (NSCLC).MethodsWe evaluated two published prognostic multi-gene biomarkers for NSCLC in an independent 442-patient dataset. We then systematically assessed how technical factors influenced validation success.ResultsBoth biomarkers validated successfully (biomarker #1: hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.21 to 2.19, P = 0.001; biomarker #2: HR 1.42, 95% CI 1.03 to 1.96, P = 0.030). Further, despite being underpowered for stage-specific analyses, both biomarkers successfully stratified stage II patients and biomarker #1 also stratified stage IB patients. We then systematically evaluated reasons for reported validation failures and find they can be directly attributed to technical challenges in data analysis. By examining 24 separate pre-processing techniques we show that minor alterations in pre-processing can change a successful prognostic biomarker (HR 1.85, 95% CI 1.37 to 2.50, P < 0.001) into one indistinguishable from random chance (HR 1.15, 95% CI 0.86 to 1.54, P = 0.348). Finally, we develop a new method, based on ensembles of analysis methodologies, to exploit this technical variability to improve biomarker robustness and to provide an independent confidence metric.ConclusionsBiomarkers comprise a fundamental component of personalized medicine. We first validated two NSCLC prognostic biomarkers in an independent patient cohort. Power analyses demonstrate that even this large, 442-patient cohort is under-powered for stage-specific analyses. We then use these results to discover an unexpected sensitivity of validation to subtle data analysis decisions. Finally, we develop a novel algorithmic approach to exploit this sensitivity to improve biomarker robustness

    The experience of adolescents in the diversion programme offered by Bokamoso Life Centre

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    Dealing with young offenders remains a universal problem around the world and South Africa is no exception. It would appear that certain factors in the community, the family and the school system may contribute to juvenile delinquency. Diversion programmes are utilized as an alternative to avoid juveniles accused of petty offences from being imprisoned. The researcher conducted this study after observing that many young people still end up in conflict with the law despite the completion of these programmes. Due to the latter, questions regarding the effectiveness of diversion programmes developed. The aim of this study was to evaluate the effectiveness of the diversion programme offered by Bokamoso Life Centre. The researcher conducted a qualitative study through which the goal of this study was achieved. Further research in this field is recommended because of the fact that this study was limited to a specific geographical area.Dissertation (MSD (Play Therapy))--University of Pretoria, 2006.Social Work and Criminologyunrestricte

    MRI and Stereo Vision Surface Reconstruction and Fusion

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    Breast cancer, the most commonly diagnosed cancer in women worldwide, is mostly detected through a biopsy where tissue is extracted and chemically examined or pathologist assessed. Medical imaging plays a valuable role in targeting malignant tissue accurately and guiding the radiologist during needle insertion in a biopsy. This paper proposes a computer software that can process and combine 3D reconstructed surfaces from different imaging modalities, particularly Magnetic Resonance Imaging (MRI) and camera, showing a visualization of important features and investigates its feasibility. The development of this software aims to combine the detectability of MRI with the physical space of the camera. It demonstrates that the registration accuracy of the proposed system is acceptable and has potential for clinical application

    Unravelling the functions of biogenic volatiles in boreal and temperate forest ecosystems

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    Living trees are the main source of biogenic volatile organic compounds (BVOCs) in forest ecosystems, but substantial emissions originate from leaf and wood litter, the rhizosphere and from microorganisms. This review focuses on temperate and boreal forest ecosystems and the roles of BVOCs in ecosystem function, from the leaf to the forest canopy and from the forest soil to the atmosphere level. Moreover, emphasis is given to the question of how BVOCs will help forests adapt to environmental stress, particularly biotic stress related to climate change. Trees use their vascular system and emissions of BVOCs in internal communication, but emitted BVOCs have extended the communication to tree population and whole community levels and beyond. Future forestry practices should consider the importance of BVOCs in attraction and repulsion of attacking bark beetles, but also take an advantage of herbivore-induced BVOCs to improve the efficiency of natural enemies of herbivores. BVOCs are extensively involved in ecosystem services provided by forests including the positive effects on human health. BVOCs have a key role in ozone formation but also in ozone quenching. Oxidation products form secondary organic aerosols that disperse sunlight deeper into the forest canopy, and affect cloud formation and ultimately the climate. We also discuss the technical side of reliable BVOC sampling of forest trees for future interdisciplinary studies that should bridge the gaps between the forest sciences, health sciences, chemical ecology, conservation biology, tree physiology and atmospheric science

    Genomic DNA functions as a universal external standard in quantitative real-time PCR

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    Real-time quantitative PCR (qPCR) is a powerful tool for quantifying specific DNA target sequences. Although determination of relative quantity is widely accepted as a reliable means of measuring differences between samples, there are advantages to being able to determine the absolute copy numbers of a given target. One approach to absolute quantification relies on construction of an accurate standard curve using appropriate external standards of known concentration. We have validated the use of tissue genomic DNA as a universal external standard to facilitate quantification of any target sequence contained in the genome of a given species, addressing several key technical issues regarding its use. This approach was applied to validate mRNA expression of gene candidates identified from microarray data and to determine gene copies in transgenic mice. A simple method that can assist achieving absolute quantification of gene expression would broadly enhance the uses of real-time qPCR and in particular, augment the evaluation of global gene expression studies

    Needs assessment to strengthen capacity in water and sanitation research in Africa:experiences of the African SNOWS consortium

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    Despite its contribution to global disease burden, diarrhoeal disease is still a relatively neglected area for research funding, especially in low-income country settings. The SNOWS consortium (Scientists Networked for Outcomes from Water and Sanitation) is funded by the Wellcome Trust under an initiative to build the necessary research skills in Africa. This paper focuses on the research training needs of the consortium as identified during the first three years of the project
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