584 research outputs found
Incorporating Local Data and KL Membership Divergence into Hard C-Means Clustering for Fuzzy and Noise-Robust Data Segmentation
Hard C-means (HCM) and fuzzy C-means (FCM) algorithms are among the most popular ones for data clustering including image data. The HCM algorithm offers each data entity with a cluster membership of 0 or 1. This implies that the entity will be assigned to only one cluster. On the contrary, the FCM algorithm provides an entity with a membership value between 0 and 1, which means that the entity may belong to all clusters but with different membership values. The main disadvantage of both HCM and FCM algorithms is that they cluster an entity based on only its self-features and do not incorporate the influence of the entity’s neighborhoods, which makes clustering prone to additive noise. In this chapter, Kullback-Leibler (KL) membership divergence is incorporated into the HCM for image data clustering. This HCM-KL-based clustering algorithm provides twofold advantage. The first one is that it offers a fuzzification approach to the HCM clustering algorithm. The second one is that by incorporating a local spatial membership function into the HCM objective function, additive noise can be tolerated. Also spatial data is incorporated for more noise-robust clustering
Photoacoustic Imaging for Cancer Diagnosis: A Breast Tumor Example
Photoacoustic (PA) imaging utilizes laser pulses to deliver energy to an examined object for the generation of ultrasonic waves. Thus, it provides a noninvasive and nonionizing imaging modality. Therefore, it has found clinical use for cancer diagnosis in different organs, e.g., breast, prostate, and thyroid nodules. It offers morphological, functional, and molecular imaging. Moreover, the oxygen saturation in a body can be computed by calculating the wavelength-dependent light absorption coefficients at two different wavelengths. In this chapter, the principle of the PA imaging is introduced for the present book
Understanding the Prospects and Potential for Improved Regional LIS Collaboration in the Developing World: An Empirical Study of LIS Departments in the GCC States
The purpose of the study was to generate information on the extent and types of collaboration occurring between academic LIS departments and faculty in the GCC states, and on the factors influencing this, to help inform policies and strategies designed to improve collaboration. This is a qualitative research study, based on interviews with Heads of LIS Departments in the GCC states. The researchers emailed all Heads of LIS Departments (n=8) in Universities within the GCC States to invite them to participate in an interview about their experiences of and views on collaboration with other LIS departments in the region. Of the (8) Heads of Departments, only 5 responded to the e-mail invitation and subsequently completed the interview. The qualitative research data generated from the interviews were analyzed using content analysis. The data were examined and a preliminary set of themes created, then, the data were re-examined and coded according to the preliminary themes. It was found that very little formal collaboration has taken place to date, but that Heads of Departments are well aware of the many potential benefits of collaboration, and the types of barriers that must be overcome to achieve this. The findings have theoretical significance relating to the potential role of LIS collaboration in developing regions more generally, and practical implications for the development of strategies and initiatives to improve collaboration in the Gulf region. A fourstage strategy development, planning, establishment and implementation model is proposed to underpin the program of work necessary to achieve this, which can also be applied to other developing regions
Metal and metalloid biorecovery using fungi
Bioleaching is a proven bioprocess for metal recovery by solution from solid matrices, while a bioprecipitation or biomineralization approach is of potential for biorecovery from solution. Fungi can directly and indirectly mediate the formation of many kinds of minerals, including oxides, phosphates, carbonates and oxalates, as well as elemental forms of metals and metalloids such as Ag, Se and Te. Fungal capabilities may offer a potentially useful contribution to biotechnological and physico-chemical methods for metal recovery.</p
X-Rays and Computed Tomography Scan Imaging: Instrumentation and Medical Applications
This chapter gives a review for both conventional X-ray and computed tomography (CT) scan imaging modalities and their medical applications. The chapter presents a brief history on the discovery of X-ray, X-ray imaging, and computed tomography scan. The linear projection for the generation of the sinogram (the detector’s signals versus the rotational angle) and the filtered backprojection for image reconstruction are discussed. Computer simulations for linear and fan beams X -ray are also presented. The chapter discusses some medical applications of both the conventional X-ray and CT scan imaging
The Geomycology of Elemental Cycling and Transformations in the Environment
Geomicrobiology addresses the roles of microorganisms in geological and geochemical processes, and geomycology is a part of this topic focusing on the fungi. Geoactive roles of fungi include organic and inorganic transformations important in nutrient and element cycling, rock and mineral bioweathering, mycogenic biomineral formation, and metal-fungal interactions. Lichens and mycorrhizas are significant geoactive agents. Organic matter decomposition is important for cycling of major biomass-associated elements, e.g., C, H, N, O, P, and S, as well as all other elements found in lower concentrations. Transformations of metals and minerals are central to geomicrobiology, and fungi affect changes in metal speciation, as well as mediate mineral formation or dissolution. Such mechanisms are components of biogeochemical cycles for metals as well as associated elements in biomass, soil, rocks, and minerals, e.g., S, P, and metalloids. Fungi may have the greatest geochemical influence within the terrestrial environment. However, they are also important in the aquatic environment and are significant components of the deep subsurface, extreme environments, and habitats polluted by xenobiotics, metals, and radionuclides. Applications of geomycology include metal and radionuclide bioleaching, biorecovery, detoxification, bioremediation, and the production of biominerals or metal(loid) elements with catalytic or other properties. Adverse effects include biodeterioration of natural and synthetic materials, rock and mineral-based building materials (e.g., concrete), cultural heritage, metals, alloys, and related substances and adverse effects on radionuclide mobility and containment. The ubiquity and importance of fungi in the biosphere underline the importance of geomycology as a conceptual framework encompassing the environmental activities of fungi.</p
Scale dependency in the hydromorphological control of a stream ecosystem functioning
Physical habitat degradation is prevalent in river ecosystems. Although still little is known about the ecological consequences of altered hydromorphology, understanding the factors at play can contribute to sustainable environmental management. In this study we aimed to identify the hydromorphological features controlling a key ecosystem function and the spatial scales where such linkages operate. As hydromorphological and chemical pressures often occur in parallel, we examined the relative importance of hydromorphological and chemical factors as determinants of leaf breakdown. Leaf breakdown assays were investigated at 82 sites of rivers throughout the French territory. Leaf breakdown data were then crossed with data on water quality and with a multi-scale hydro- morphological assessment (i.e. upstream catchment, river segment, reach and habitat) when quantitative data were available. Microbial and total leaf breakdown rates exhibited differential responses to both hydromorphological and chemical alterations. Relationships between the chemical quality of the water and leaf breakdown were weak, while hydromorphological integrity explained independently up to 84.2% of leaf breakdown. Hydrological and morphological parameters were the main predictors of microbial leaf breakdown, whereas hydrological parameters had a major effect on total leaf breakdown, particularly at large scales, while morphological parameters were important at smaller scales. Microbial leaf breakdown were best predicted by hydromorphological features defined at the upstream catchment level whereas total leaf breakdown were best predicted by reach and habitat level geomorphic variables. This study demonstrates the use of leaf breakdown in a biomonitoring context and the importance of hydromorphological integrity for the functioning of running water. It provides new insights for envi- ronmental decision-makers to identify the management and restoration actions that have to be un- dertaken including the hydromorphogical features that should be kept in minimal maintenance to support leaf breakdown
Evaluation of the role of glutathione in the lead-induced toxicity in Saccharomyces cerevisiae
The effect of intracellular reduced glutathione (GSH) in the lead stress response of Saccharomyces cerevisiae was investigated. Yeast cells exposed to Pb, for 3 h, lost the cell proliferation capacity (viability) and decreased intracellular GSH level. The Pb-induced loss of cell viability was compared among yeast cells deficient in GSH1 (∆gsh1) or GSH2 (∆gsh2) genes and wild-type (WT) cells. When exposed to Pb, ∆gsh1 and ∆gsh2 cells did not display an increased loss of viability, compared with WT cells. However, the depletion of cellular thiols, including GSH, by treatment of WT cells with iodoacetamide (an alkylating agent, which binds covalently to thiol group), increased the loss of viability in Pb-treated cells. In contrast, GSH enrichment, due to the incubation of WT cells with amino acids mixture constituting GSH (l-glutamic acid, l-cysteine and glycine), reduced the Pb-induced loss of proliferation capacity. The obtained results suggest that intracellular GSH is involved in the defence against the Pb-induced toxicity; however, at physiological concentration, GSH seems not to be sufficient to prevent the Pb-induced loss of cell viability
Improving Abiotic Stress Resistance In Cauliflower (Brassica oleracea var. botrytis L.) By Mutagenesis And Agrobacterium Mediated Transformation
Abiotic environmental stress such as drought, salinity and low temperature are common conditions that adversely affect plant growth and crop production. Breeding for crop resistance to abiotic stress is difficult due to its multigenic nature. An alternative approach is through DNA mutation and DNA transfer. These approaches were employed and tested in this research and comparison between them was carried out. NEU and NMU induced mutant lines and control plants were sub-cultured many times on maintenance medium and stored at 5°c for 2 years and then tested for salt and hydroxyproline resistance as in-vitro and in-vivo plants and proline content was measured. Non-acclimated and acclimated in-vivo plants were also assessed for resistance to freezing. Control plants had little or no NaCI or hydroxyproline resistance whilst selected plants showed varying degrees of resistance. In-vitro and in-vivo responses of selected lines were correlated. Leaf proline content was increased markedly in the mutant lines and the greatest proline contents occurred following NaCI stress with the most respondent line having 100 fold levels compared to the controls. Both non-acclimated and acclimated selected lines showed improved frost resistance over controls. The results clearly demonstrated that NaCI, frost and hydroxyproline resistance were stable traits over repeated in-vitro subcultures and prolonged low temperature storage. A complete range of mutants with single, double or triple resistance traits were produced. The level of resistance however was not necessarily correlated with the level of proline and some lines showed resistance without elevated proline. It is concluded that elevated proline is not essential for improved resistance to abiotic stress in cauliflower, but where it does occur it does improve resistance. Integration of APX and SOD stress genes into cauliflower (Brassica oleracea var. botrytis L.) plants was achieved by using Agrobacterium tumefaciens – mediated transformation method. The procedure utilized polymerase chain reaction (PCR) amplification of insert DNA directly after isolation of individual colonies without the necessity of separate procedures for DNA isolation and purification. Preliminary selection of transgenic plants was performed on different combinations of kanamycin, gentamycin and tetracycline containing medium. Integration of the introduced stress gene (APX and SOD) in the plants was confirmed by using β-glucuronidase gene (GUS) and leaf disc assays as a gene fusion and diagnostic marker, respectively. The stable integration of the APX and SOD gene at 478 bp was detected by using polymerase chain reaction (PCR) of the putative transgenic plants. Analysis of APX and SOD gene expression under salt treatment showed that putative transgenic cauliflower survived the salinity stress comparing with the control plants
Developing Road Roughness Deterioration Models for Pavement Management System in Developing Countries, Case Study: Lao People's Democratic Republic
Nagasaki University (長崎大学)博士(工学)長崎大学学位論文 学位記番号:博(工)甲第115号 学位授与年月日:令和4年3月18日Nagasaki University (長崎大学), 博士(工学) (2022-03-18)doctoral thesi
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