433 research outputs found

    Investigation of Mortgage Lending: An Overview of Nigerian Practice

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    There has been a growing concern on the rate of default in residential mortgages of lending institutions in Nigeria. The need to salvage the undesirable situation has led to serious research efforts on factors causing default in residential mortgages. The paper therefore assesses the lending practice of lending institutions as possible cause of residential mortgage default. One (1) set of questionnaire was administered on Primary Mortgage Institutions (PMIs) across the Lagos metropolis with the intent of eliciting relevant information. Out of Sixty-five (65) questionnaires administered, only Thirty-six (36) were returned and found good for analysis. Data analysis was done using weighted mean score and rank correlation analysis. It was found that statistical based credit models are seldom used by the lenders while the evolving role of information technology in mortgage lending is yet to be given due attention. Keywords: default, finance, mortgage, practice, residential

    Hexamethonium produces both twitch and tetanic depression without fade in common African toad (Bufo regularis)

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    The study was designed to investigate the nature of the cholinoceptors at the sciatic nervegastrocnemius muscle junction of the common African toad (Bufo regularis). Using myographic technique, the twitch properties of the sciatic-gastrocnemius muscle preparation of the common African toad was studied. Both the twitch height and peak tetanic height were measured as a percentage of control. Hexamethonium at a concentratration of 0.1mM significantly (

    Evolution of a qubit under the influence of a succession of unsharp measurements

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    We investigate the evolution of a single qubit subject to a continuous unitary dynamics and an additional interrupting influence which occurs periodically. One may imagine a dynamically evolving closed quantum system which becomes open at certain times. The interrupting influence is represented by an operation, which is assumed to equivalently describe a non-selective unsharp measurement. It may be decomposed into a positive operator, which in case of a measurement represents the pure measurement part, followed by an unitary back-action operator. Equations of motion for the state evolution are derived in the form of difference equations. It is shown that the 'free' Hamiltonian is completed by an averaged Hamiltonian, which goes back to the back-action. The positive operator specifies a decoherence rate and results in a decoherence term. The continuum limit to a master equation is performed. The selective evolution is discussed and correcting higher order terms are worked out in an Appendix.Comment: 19 pages, no figure

    Biological Resolution of Virulence Genes of Salmonella Species from different Microbiomes

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    The pathogenic promiscuity of virulence associated macromolecules in Salmonella infection is a key driver to their wide epidemiology and curtailing  such distribution is contingent upon proper clarification of these virulence genes. This study was therefore aimed at determining the virulence  genes of Salmonella species from different microbiomes. To achieve this, a total of three hundred (300) biological specimens were aseptically  collected and processed for Salmonella presence using the BAM USFDA technique prior to their genotypic characterization while virulence gene  detection was carried out in a primer specific polymerase chain reaction. Results obtained depict the distribution of the following Salmonella species  viz; Salmonella gallinarum 19(26.39%), Salmonella heidelberg 19(26.39%), Salmonella enteritidis 18(25%) and Salmonella typhimurium  16(22.22%) while the occurrence of the virulence genes (InvA, SopE, AgfA and SpvC) were Salmonella enteritidis ( 7(38.8), 6(33.3), 9(50), 3(16.7),  Salmonella typhimurium ( 5(26.3), 3(15.8), 2(10.5), 7(36.8)), Salmonella heidelberg (0(0), 8(50), 4(25), 4(25), and Salmonella gallinarum (12(63.2),  6(31.6), 2(10.5), 7(36.8)) respectively. It was however found that the different microbiomes analyzed were ubiquitously rich in virulence genes  associated Salmonella species.   La promiscuité pathogène des macromolécules associées à la virulence dans l’infection à Salmonella est un facteur clé de leur large épidémiologie  et la réduction de cette distribution dépend de la clarification appropriée de ces gènes de virulence. Cette étude visait donc à déterminer les gènes  de virulence des espèces de Salmonella de différents microbiomes. Pour ce faire, un total de trois cents (300) échantillons biologiques ont été  collectés et traités de manière aseptique pour la présence de Salmonella à l’aide de la technique BAM USFDA avant leur caractérisation génotypique  tandis que la détection du gène de virulence a été effectuée dans une réaction en chaîne par polymérase spécifique à l’amorce. Les résultats  obtenus décrivent la distribution des espèces de Salmonella suivantes, à savoir ; Salmonella gallinarum 19(26,39%), Salmonella heidelberg  19(26,39%), Salmonella enteritidis 18(25%) et Salmonella typhimurium 16(22,22%) alors que la présence des gènes de virulence (InvA, SopE, AgfA et  SpvC) était Salmonella enteritidis ( 7(38,8), 6(33,3), 9(50), 3(16,7), Salmonella typhimurium ( 5(26,3), 3(15,8), 2(10,5), 7(36,8)), Salmonella heidelberg (0(  0), 8(50), 4(25), 4(25) et Salmonella gallinarum (12(63.2), 6(31.6), 2(10.5), 7(36.8)) respectivement. différents microbiomes analysés étaient  ubiquitairement riches en gènes de virulence associés aux espèces de Salmonella  &nbsp

    Generic Feature Extraction for Classification using Fuzzy C - Means Clustering

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    Knowledge discovery and data mining (KDD) process includes preprocessing, transformation, data mining and knowledge extraction. The two important tasks of data mining are clustering and classification. In this paper, we propose a generic feature extraction for classification using fuzzy C-means (FCM) clustering. The raw data is preprocessed, normalized and then data points are clustered using the fuzzy C-means technique. Feature vectors for all the classes are generated by extracting the most relevant features from the corresponding clusters and used for further classification. Artificial neural network and support vector machines are used to perform the classification task. Experiments are conducted on four datasets and the accuracy obtained by performing specific feature extraction for a particular data set is compared with the generic feature extraction scheme. The algorithm performs relatively well with respect to classification results when compared with the specific feature extraction techniqu

    Coherence Window in the dynamics of Quantum Nanomagnets

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    Decoherence in many solid-state systems is anomalously high, frustrating efforts to make solid-state qubits. We show that in nanomagnetic insulators in large transverse fields, there can be a fairly narrow field region in which both phonon and nuclear spin-mediated decoherence are drastically reduced. As examples we calculate decoherence rates for the FeFe-8 nanomolecule, for NiNi particles, and for HoHo ions in LiHoxY1zF4LiHo_xY_{1-z}F_4. The reduction in the decoherence, compared to low field rates, can exceed 6 orders of magnitude. The results also give limitations on the observability of macroscopic coherence effects in magnetic systems.Comment: 5 LaTeX pages, 3 figure

    Seed degeneration in potato : the need for an integrated seed health strategy to mitigate the problem in developing countries

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    Seed potato degeneration, the reduction in yield or quality caused by an accumulation of pathogens and pests in planting material due to successive cycles of vegetative propagation, has been a long-standing production challenge for potato growers around the world. In developed countries this problem has been overcome by general access to and frequent use of seed, produced by specialized growers, that has been certified to have pathogen and pest incidence below established thresholds, often referred to as certified seed. The success of certified seed in developed countries has concentrated the research and development agenda on the establishment of similar systems in developing countries. Despite these efforts, certified seed has had little penetration into the informal seed systems currently in place in most developing countries. Small-scale farmers in these countries continue to plant seed tubers acquired through the informal seed system, i.e. produced on-farm or acquired from neighbours or local markets. Informal seed tubers frequently have poor health status, leading to significant reductions in yield and/or market value. This review emphasizes the need to refocus management efforts in developing countries on improving the health status of seed tubers in the informal system by integrating disease resistance and on-farm management tools with strategic seed replacement. This 'integrated seed health strategy' can also prolong the good health status of plants derived from certified seed, which would otherwise be diminished due to potential rapid infection from neighbouring fields. Knowledge gaps, development challenges and impacts of this integrated seed health strategy are discussed.PostprintPeer reviewe

    Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.

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    Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants

    Large-amplitude driving of a superconducting artificial atom: Interferometry, cooling, and amplitude spectroscopy

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    Superconducting persistent-current qubits are quantum-coherent artificial atoms with multiple, tunable energy levels. In the presence of large-amplitude harmonic excitation, the qubit state can be driven through one or more of the constituent energy-level avoided crossings. The resulting Landau-Zener-Stueckelberg (LZS) transitions mediate a rich array of quantum-coherent phenomena. We review here three experimental works based on LZS transitions: Mach-Zehnder-type interferometry between repeated LZS transitions, microwave-induced cooling, and amplitude spectroscopy. These experiments exhibit a remarkable agreement with theory, and are extensible to other solid-state and atomic qubit modalities. We anticipate they will find application to qubit state-preparation and control methods for quantum information science and technology.Comment: 13 pages, 5 figure
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