125 research outputs found

    Church and Formation of Conscience: Towards A Liberative Ecclesiology for Peace and Justice in Kenya

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    Kenya, like many other African countries, continues to experience, fifty years after independence, various challenges including political instability and violence resulting from negative ethnicity. Kenya‘s history is rife with examples of divisive politics and negative ethnicity ranging from ethnic violence, ethnicized politics, dictatorship of the ethnic majority and ethnic clashes. Evidence of the deeply seated hatred can be found in the apparent reality of ethnic division and intertribal clashes often experienced either before, during or after elections. The 2007 post-election violence which claimed over 1300 lives and the displacement of more than 300,000 people demonstrated the depth of the culture of negative ethnicity. This violence, together with previous intertribal clashes especially experienced in the country in the 1990s, exposed a thorny issue regarding the impact of a deformed conscience in society. It demonstrates the extent to which human actions based on blind choices can cause immense human suffering and loss of life. This study proposes a liberative ecclesiology based on the formation of conscience as a pastoral strategy from below capable of renewing moral imagination and reawakening of the moral endowment inherent in every human being. The strength of this ecclesiology lies in the fact that it integrates both the top-down and bottom-up approaches capable of fostering the kind of social agents capable of creating a just and peaceful society. The characteristics of this ecclesiology include expanding moral imagination through telling and sharing stories and myths, and historicizing the formation of conscience in the Small Christian Communities (SCCs) through educational and formational programs

    Structure and Function in Degraded Forests in the Amazon from Multi-source Remote Sensing

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    University of Technology Sydney. Faculty of Science.Tropical forests provide critical ecosystem services for global climate and biodiversity, and sustain the livelihoods of millions of people. Yet, they have become hotspots of land-use change. The Southern border of the Brazilian Amazon has been a focus of land development with large swaths of tropical forests converted to agriculture. Degradation of forests by selective logging and fires has accompanied the advance of the frontier and has resulted in significant impacts on Amazonian ecosystems. While the agricultural use in the region is well quantified, forest degradation is more challenging to study. Given that changes in tree cover and structure have large impacts on forest function, there is an urgent need to quantify these properties for degraded forests. The overarching goal of this thesis is to investigate the functional and structural linkages in degraded forests in the Amazon and assess whether forest structure mediates forest responses to disturbance. To achieve this goal, I (1) compared phenological patterns of intact and degraded forests using time-series of spectral indices; (2) examined the relationship between forest structure and photosynthesis across a gradient of forest degradation, by integrating structural variables and solar-induced fluorescence (SIF) data; and finally, (3) investigated the influence of forest structure on evapotranspiration and land surface temperature. These broad thesis objectives were accomplished using multi-source remote sensing (MODIS, Landsat and TROPOMI SIF satellite data combined with airborne and orbital lidar observations) and statistical methods. My results showed that fires had a stronger effect than selective logging on ecosystem functioning (e.g., stronger phenological shifts and alterations in evapotranspiration and land surface temperature) and caused more dramatic changes in forest structure (e.g., lower forest canopy and leaf area index, more abundant understory). I also found that shifts in ecosystem functioning related to forest degradation were exacerbated by the dry season in the study region. Finally, I found that the most heavily disturbed forests presented strong structure-function relationships that do not hold in the least disturbed forests, suggesting that forest structure acts as a mediator of forest recovery. My findings help to elucidate the effects of human-induced disturbances in ecosystem fluxes and can inform public policy related to forest management and land use planning. Besides, my results provide inputs regarding the role of phenology and forest structure in degraded forests for ecosystem demography models. The importance of this research is underscored by the recent surge in deforestation in the Brazilian Amazon and associated forest fires

    Proline transport by Salmonella typhimurium regulation of the PUTP permease and activation of a new proline permease

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    Thesis (B.S) in Biology -- University of Illinois at Urbana-Champaign, 1989.Includes bibliographical references (leaves38-39).Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1989]. 2 microfiches (41 frames): negative.s 1989 ilu n

    Detection of logging infrastructure in the state of Rondônia using remotely sensed data

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    A infraestrutura para exploração florestal é fundamental nas atividades de exploração madeireira, mas responde por grande parte dos impactos ambientais dessa atividade. O presente estudo aplicou e testou cinco técnicas de processamento digital de imagens orbitais com três resoluções espaciais distintas para a detecção de estradas e pátios florestais construídos em áreas sob manejo florestal sustentável na Floresta Nacional do Jamari, estado de Rondônia. Os resultados mostraram que o NDVI e a Análise de componentes principais apresentaram a melhor acurácia global nas resoluções espaciais de 5 e 10 metros e na de 30 metros, respectivamente. De maneira geral, a acurácia do produtor para a classe de interesse não foi alta, alcançando no máximo 39,2%, e índice Kappa de 0,38. A baixa performance das técnicas de geoprocessamento utilizadas na detecção de florestas exploradas seletivamente está relacionada às alterações ocorridas no dossel da floresta manejada, pouco perceptíveis em imagens de satélite.Logging lands (forest roads and log decks) are an underlying issue during selective logging activities, but they are responsible for most impacts on the forest. This study aimed to apply and assess the performance of five geoprocessing techniques on remotely sensed data using three different spatial resolutions to detect logging lands under forest management at the Jamari National Forest, state of Rondônia, Brazil. The research results showed that Normalized Difference Vegetation Index (NDVI) and Principal Components Analysis (PCA) presented the best overall accuracy using spatial resolutions of 5 and 10 meters, and 30 meters, respectively. Generally, the overall accuracy and Kappa statistics for the selectively logged forest classifications were not good (39.2% or lower, and 0.38 or lower, respectively). The low performance of the geoprocessing techniques is related to the subtle changes on the forest canopy cover under selective logging activities

    Long-Term Impacts of Selective Logging on Amazon Forest Dynamics from Multi-Temporal Airborne LiDAR

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    Forest degradation is common in tropical landscapes, but estimates of the extent and duration of degradation impacts are highly uncertain. In particular, selective logging is a form of forest degradation that alters canopy structure and function, with persistent ecological impacts following forest harvest. In this study, we employed airborne laser scanning in 2012 and 2014 to estimate three-dimensional changes in the forest canopy and understory structure and aboveground biomass following reduced-impact selective logging in a site in Eastern Amazon. Also, we developed a binary classification model to distinguish intact versus logged forests. We found that canopy gap frequency was significantly higher in logged versus intact forests even after 8 years (the time span of our study). In contrast, the understory of logged areas could not be distinguished from the understory of intact forests after 67 years of logging activities. Measuring new gap formation between LiDAR acquisitions in 2012 and 2014, we showed rates 2 to 7 times higher in logged areas compared to intact forests. New gaps were spatially clumped with 76 to 89% of new gaps within 5 m of prior logging damage. The biomass dynamics in areas logged between the two LiDAR acquisitions was clearly detected with an average estimated loss of -4.14 +/- 0.76 MgC/hay. In areas recovering from logging prior to the first acquisition, we estimated biomass gains close to zero. Together, our findings unravel the magnitude and duration of delayed impacts of selective logging in forest structural attributes, confirm the high potential of airborne LiDAR multitemporal data to characterize forest degradation in the tropics, and present a novel approach to forest classification using LiDAR data

    Genomic RNA Elements Drive Phase Separation of the SARS-CoV-2 Nucleocapsid

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    We report that the SARS-CoV-2 nucleocapsid protein (N-protein) undergoes liquid-liquid phase separation (LLPS) with viral RNA. N-protein condenses with specific RNA genomic elements under physiological buffer conditions and condensation is enhanced at human body temperatures (33°C and 37°C) and reduced at room temperature (22°C). RNA sequence and structure in specific genomic regions regulate N-protein condensation while other genomic regions promote condensate dissolution, potentially preventing aggregation of the large genome. At low concentrations, N-protein preferentially crosslinks to specific regions characterized by single-stranded RNA flanked by structured elements and these features specify the location, number, and strength of N-protein binding sites (valency). Liquid-like N-protein condensates form in mammalian cells in a concentration-dependent manner and can be altered by small molecules. Condensation of N-protein is RNA sequence and structure specific, sensitive to human body temperature, and manipulatable with small molecules, and therefore presents a screenable process for identifying antiviral compounds effective against SARS-CoV-2

    Estrogen receptor transcription and transactivation: Estrogen receptor alpha and estrogen receptor beta - regulation by selective estrogen receptor modulators and importance in breast cancer

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    Estrogens display intriguing tissue-selective action that is of great biomedical importance in the development of optimal therapeutics for the prevention and treatment of breast cancer, for menopausal hormone replacement, and for fertility regulation. Certain compounds that act through the estrogen receptor (ER), now referred to as selective estrogen receptor modulators (SERMs), can demonstrate remarkable differences in activity in the various estrogen target tissues, functioning as agonists in some tissues but as antagonists in others. Recent advances elucidating the tripartite nature of the biochemical and molecular actions of estrogens provide a good basis for understanding these tissue-selective actions. As discussed in this thematic review, the development of optimal SERMs should now be viewed in the context of two estrogen receptor subtypes, ERα and ERβ, that have differing affinities and responsiveness to various SERMs, and differing tissue distribution and effectiveness at various gene regulatory sites. Cellular, biochemical, and structural approaches have also shown that the nature of the ligand affects the conformation assumed by the ER-ligand complex, thereby regulating its state of phosphorylation and the recruitment of different coregulator proteins. Growth factors and protein kinases that control the phosphorylation state of the complex also regulate the bioactivity of the ER. These interactions and changes determine the magnitude of the transcriptional response and the potency of different SERMs. As these critical components are becoming increasingly well defined, they provide a sound basis for the development of novel SERMs with optimal profiles of tissue selectivity as medical therapeutic agents

    Expression of oestrogen receptor beta (ERβ1) protein in human breast cancer biopsies

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    Oestrogen action is mediated via specific receptors that act as ligand-activated transcription factors. A monoclonal antibody specific to the C-terminus of human oestrogen receptor beta has been characterized and the prevalence of expression of oestrogen receptor beta protein investigated in a well defined set of breast cancers. Reverse transcription-polymerase chain reaction analysis of RNA from tissue biopsies detected oestrogen receptor beta in all samples examined. The anti-oestrogen receptor beta antibody cross reacted specifically with both long (∼59 Kd) and short (∼53 Kd) forms of recombinant oestrogen receptor beta. Western blot analysis of breast tumours contained both forms of oestrogen receptor beta protein although in some samples lower molecular weight species (32–45 Kd) were identified. Fifty-one breast cancer biopsies were examined using immunohistochemistry; 41 (80%) were immunopositive for oestrogen receptor alpha, 48 (94%) were immunopositive for oestrogen receptor beta and 38 (74.5%) co-expressed both receptors. Expression of oestrogen receptor beta was exclusively nuclear and occurred in multiple cell types. There was no quantitative relationship between staining for the two ERs although in tumours in which both receptors were present immunoexpression of oestrogen receptor alpha was invariably more intense. The significance of oestrogen receptor beta protein expression in breast cancers to therapy remains to be determined but the availability of a well characterized antibody capable of detecting oestrogen receptor beta in archive material will facilitate the process

    Systematic Deletion of Homeobox Genes in Podospora anserina Uncovers Their Roles in Shaping the Fruiting Body

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    Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures

    Genetic interactions between a phospholipase A2 and the Rim101 pathway components in S. cerevisiae reveal a role for this pathway in response to changes in membrane composition and shape

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    Modulating composition and shape of biological membranes is an emerging mode of regulation of cellular processes. We investigated the global effects that such perturbations have on a model eukaryotic cell. Phospholipases A2 (PLA2s), enzymes that cleave one fatty acid molecule from membrane phospholipids, exert their biological activities through affecting both membrane composition and shape. We have conducted a genome-wide analysis of cellular effects of a PLA2 in the yeast Saccharomyces cerevisiae as a model system. We demonstrate functional genetic and biochemical interactions between PLA2 activity and the Rim101 signaling pathway in S. cerevisiae. Our results suggest that the composition and/or the shape of the endosomal membrane affect the Rim101 pathway. We describe a genetically and functionally related network, consisting of components of the Rim101 pathway and the prefoldin, retromer and SWR1 complexes, and predict its functional relation to PLA2 activity in a model eukaryotic cell. This study provides a list of the players involved in the global response to changes in membrane composition and shape in a model eukaryotic cell, and further studies are needed to understand the precise molecular mechanisms connecting them
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