1,992 research outputs found

    Approximations from Anywhere and General Rough Sets

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    Not all approximations arise from information systems. The problem of fitting approximations, subjected to some rules (and related data), to information systems in a rough scheme of things is known as the \emph{inverse problem}. The inverse problem is more general than the duality (or abstract representation) problems and was introduced by the present author in her earlier papers. From the practical perspective, a few (as opposed to one) theoretical frameworks may be suitable for formulating the problem itself. \emph{Granular operator spaces} have been recently introduced and investigated by the present author in her recent work in the context of antichain based and dialectical semantics for general rough sets. The nature of the inverse problem is examined from number-theoretic and combinatorial perspectives in a higher order variant of granular operator spaces and some necessary conditions are proved. The results and the novel approach would be useful in a number of unsupervised and semi supervised learning contexts and algorithms.Comment: 20 Pages. Scheduled to appear in IJCRS'2017 LNCS Proceedings, Springe

    (k,q)-Compressed Sensing for dMRI with Joint Spatial-Angular Sparsity Prior

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    Advanced diffusion magnetic resonance imaging (dMRI) techniques, like diffusion spectrum imaging (DSI) and high angular resolution diffusion imaging (HARDI), remain underutilized compared to diffusion tensor imaging because the scan times needed to produce accurate estimations of fiber orientation are significantly longer. To accelerate DSI and HARDI, recent methods from compressed sensing (CS) exploit a sparse underlying representation of the data in the spatial and angular domains to undersample in the respective k- and q-spaces. State-of-the-art frameworks, however, impose sparsity in the spatial and angular domains separately and involve the sum of the corresponding sparse regularizers. In contrast, we propose a unified (k,q)-CS formulation which imposes sparsity jointly in the spatial-angular domain to further increase sparsity of dMRI signals and reduce the required subsampling rate. To efficiently solve this large-scale global reconstruction problem, we introduce a novel adaptation of the FISTA algorithm that exploits dictionary separability. We show on phantom and real HARDI data that our approach achieves significantly more accurate signal reconstructions than the state of the art while sampling only 2-4% of the (k,q)-space, allowing for the potential of new levels of dMRI acceleration.Comment: To be published in the 2017 Computational Diffusion MRI Workshop of MICCA

    Increased sample asymmetry and memory of cardiac time-series following endotoxin administration in cirrhotic rats

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    Sepsis, and other causes of acute systemic inflammation, can reduce heart rate variability (HRV) and increase cardiac cycle regularity in mammals. Thus, HRV monitoring has been used for early detection of sepsis in adults and neonates. Liver cirrhosis is associated with reduced basal HRV and the development of tolerance to the cardiac chronotropic effects of bacterial endotoxin. This may pose limitations on the use of heart rate monitoring in early detection of sepsis in this patient population. In a study to develop a physiomarker for the detection of sepsis in cirrhosis, we observed that endotoxin administration in adult cirrhotic rats leads to the development of transient heart rate decelerations, a phenomenon which has been reported in neonates with sepsis, and quantified using sample asymmetry analysis. In the present study, cirrhosis was induced by surgical ligation of the bile duct in rats. Cirrhotic rats were given intraperitoneal injections of either saline or endotoxin (1 mg kg(-1)). Changes in sample asymmetry and memory length of cardiac time-series were studied in conscious rats using implanted telemetric probes. Cirrhotic (but not control) rats exhibited increased sample asymmetry following endotoxin injection, which was consistent with the development of transient heart rate deceleration. Endotoxin administration in cirrhotic rats was associated with prolongation of memory length for observing decelerating perturbations in the cardiac rhythm. These findings may have application in the development of an HRV monitoring system for early detection of sepsis in cirrhosis

    In-field soil fertility assessment of Ramat Polytechnic farm Maiduguri in North-Eastern Nigeria

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    In-field soil fertility valuation is an important diagnostic tool for determining the nutrient needs of plants. The main objective was to determine soil chemical characteristics. Twenty samples covering 2.5 hectares of the farm from 0-30 cm depth (< 2mm fraction) processed and analysed in the laboratory. The soils are in a state of equilibrium from the C: N ratio (14.50 to 35.00), influencing the biogeochemistry of carbon, nitrogen, and phosphorus in pedogenetic development. There was high exchangeable calcium (6.20 Cmolkg-1 to 12.40 Cmolkg-1) and magnesium (1.00Cmolkg-1 to 4.80Cmolkg-1). Potassium contents were found to be medium to high (0.27 Cmolkg-1 to 1.54 Cmolkg-1). Available phosphorus ranged from low to medium contents (1.40 mkg-1 to 22.05 mkg-1) in all the samples. Cation exchange capacity (CEC) ranged from 10.01 Cmolkg-1 to 0.41 Cmolkg-1 and percent base saturation was high having >80%. Parent materials (sedimentary deposits) had influenced the availability of phosphorus and the exchangeable bases on the farm. These findings conclude that the soils have a high fertility status. However, there are slight hazards of salinity

    Current-induced membrane discharge

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    Possible mechanisms for over-limiting current (OLC) through aqueous ion-exchange membranes (exceeding diffusion limitation) have been debated for half a century. Flows consistent with electro-osmotic instability (EOI) have recently been observed in microfluidic experiments, but the existing theory neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge" (CIMD), even in the absence of fluid flow. Salt depletion leads to a large electric field which expels water co-ions, causing the membrane to discharge and lose its selectivity. Since salt co-ions and water ions contribute to OLC, CIMD interferes with electrodialysis (salt counter-ion removal) but could be exploited for current-assisted ion exchange and pH control. CIMD also suppresses the extended space charge that leads to EOI, so it should be reconsidered in both models and experiments on OLC.Comment: 4.5 page

    Overlimiting Current and Shock Electrodialysis in Porous Media

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    Most electrochemical processes, such as electrodialysis, are limited by diffusion, but in porous media, surface conduction and electro-osmotic flow also contribute to ionic fluxes. In this paper, we report experimental evidence for surface-driven over-limiting current (faster than diffusion) and deionization shocks (propagating salt removal) in a porous medium. The apparatus consists of a silica glass frit (1 mm thick with 500 nm mean pore size) in an aqueous electrolyte (CuSO4_4 or AgNO3_3) passing ionic current from a reservoir to a cation-selective membrane (Nafion). The current-voltage relation of the whole system is consistent with a proposed theory based on the electro-osmotic flow mechanism over a broad range of reservoir salt concentrations (0.1 mM - 1.0 M), after accounting for (Cu) electrode polarization and pH-regulated silica charge. Above the limiting current, deionized water (≈10μ\approx 10 \mu MM) can be continuously extracted from the frit, which implies the existence of a stable shock propagating against the flow, bordering a depleted region that extends more than 0.5mm across the outlet. The results suggest the feasibility of "shock electrodialysis" as a new approach to water desalination and other electrochemical separations.Comment: 39 pages, 9 fig

    Social Communication of Predator-Induced Changes in Drosophila Behavior and Germ Line Physiology

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    Behavioral adaptation to environmental threats and subsequent social transmission of adaptive behavior has evolutionary implications. In Drosophila, exposure to parasitoid wasps leads to a sharp decline in oviposition. We show that exposure to predator elicits both an acute and learned oviposition depression, mediated through the visual system. However, long-term persistence of oviposition depression after predator removal requires neuronal signaling functions, a functional mushroom body, and neurally driven apoptosis of oocytes through effector caspases. Strikingly, wasp-exposed flies (teachers) can transmit egg-retention behavior and trigger ovarian apoptosis in naive, unexposed flies (students). Acquisition and behavioral execution of this socially learned behavior by naive flies requires all of the factors needed for primary learning. The ability to teach does not require ovarian apoptosis. This work provides new insight into genetic and physiological mechanisms that underlie an ecologically relevant form of learning and mechanisms for its social transmission

    Faktor-faktor yang mempengaruhi peningkatan minat masuk seminari

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    Seminary is an educational place (dormitory and school) which is devoted to children who have the desire to become priests. These young people are nurtured by the teaching staff of the priests. This study aims to examine the influence of seminary promotion factors, student religiosity, social media and students' understanding of seminary so that they are interested in joining the seminary. Quantitative research was conducted using a survey method by distributing questionnaires to 100 generation Z students of SMP Panca Setya 2 Sintang from January 2021 to April 2021. The results showed that seminary promotion and social media had a significant effect on understanding and interest in seminary. However, student religiosity has no significant effect on interest in entering the seminary. Conclusion: Interest in entering seminary is influenced by seminary promotion, social media and students' understanding of seminary. Therefore seminaries need to increase promotion of seminary, social media and understanding of Generation Z students about seminary in an effort to increase student interest in entering seminary

    Optimisation and comparison of transient expression methods to express the green fluorescent protein in the obligate biotrophic oomycete Plasmopara viticola

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    Grape downy mildew is caused by Plasmopara viticola, an obligate biotrophic oomycete and a major pathogen of grapevine. Studying obligate biotrophic pathogens is difficult as they cannot grow without their host. We therefore attempted to develop a method where the pathogen could be visualized and quantified in planta without killing the host plant. To this end P. viticola was transformed with the marker gene gfp coding for the green fluorescent protein. Various transformation methods, namely electroporation, particle bombardment and transformation with Agrobacterium tumefaciens were applied. Although some methods yielded positive transformation events, no stable strain of P. viticola expressing gfp could be generated. Using the electroporation method, we obtained transient P. viticola transformants expressing gfp over 4 generations. In contrast, particle bombardment failed in transforming P. viticola. Transformation with A. tumefaciens had a low efficiency, only some structures were fluorescent and fluorescence was never observed in the subsequent generations.
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