3,548 research outputs found

    Variability, correlation and path co-eeficient analysis for yield and its components in rice

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    Direct selection based on crop yields is often a paradox in breeding programmes because yield is a complex polygenically inherited character, influenced by its component traits. Breeding programmes should, therefore, take into consideration character association of various component traits with yield and among themselves. Inthis study, fourteen rice (Oryza sativa L.) genotypes at the Gezira Research Station Farm (GRSF), Sudan were assessed for genetic variability and correlations between yield and yield components among phenotypic markers and polygenic trait analysis. A wider genetic variability was observed among the genotypes for most of thecharacters studied. The highest genotypic coefficient of varation was recorded for grain yield, percent unfilled grain panicle-1, number of grains panicle-1 and number of filled grain panicle-1. Phenotypic correlations between grain yield and number of filled grain panicle-1, number of panicle m-2 and 1000 grain weight were 0.52, 0.36 and0.27, respectively. These results suggested that improvement in yield could be attained by selecting rice plants for higher number of filled grain panicle-1, number of panicle m-2, and 1000 grain weight. The path analysis revelead that number of filled grains panicle-1 had direct positive (0.87) contribution to the grain yield ha-1 and positive (0.33) indirect effect on grain yield ha-1 through days to 50% maturity and number of grains panicle-1 (0.089); while number of filled grains per particle had negative (-0.30) and (-0.21) indirect effect on grain yieldha-1 through number of tillers plant-1 and number of panicles m-2, respectively. The relative contribution of characters towards variability and results of correlation and path coefficient indicated the importance of number of grain panicle-1, number of filled grain panicle-1 and number of panicle m-2. Genotypes having these characters would offer a good possibility for the improvement of rice through conventional selection

    Admission control for a capacitated supply system with real-time replenishment information

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    Control towers can provide real-time information on logistic processes to support decision making. The question however, is how to make use of it and how much it may save. We consider this issue for a company supplying expensive spare parts and which has limited production capacity. Besides deciding on base stock levels, it can accept or reject customers. The real-time status information is captured by a k-Erlang distributed replenishment lead time. First we model the problem with patient customers as an infinite-horizon Markov decision process and minimize the total expected discounted cost. We prove that the optimal policy can be characterized using two thresholds: a base work storage level that determines when ordering takes place and an acceptance work storage level that determines when demand of customers should be accepted. In a numerical study, we show that using real-time status information on the replenishment item and adopting admission control can lead to significant cost savings. The cost savings are highest when the optimal admission threshold is a work storage level with a replenishment item halfway in process. This finding is different from the literature, where it is stated that the cost increase of ignoring real-time information is negligible under either the lost sales or the backordering case. Next we study the problem where customers are of limited patience. We find that the optimal admission policy is not always of threshold type. This is different from the literature which assumes an exponential production lead time.</p

    Comprehensive gait analysis of healthy older people: unveiling reasons for lack of long-distance walking

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    Many older adults do not adhere to the recommended physical activity levels. This study examines the gait changes upon long-distance walking among healthy older adults. Gait tests of 24 adults aged 65 or more were conducted at the baseline, at the end of 30 and 60 minutes of treadmill walk. Spatial temporal, kinematic and kinetic gait data were computed. Perceived level of exertion was evaluated for each subject. Ten subjects (Group B) perceived higher exertion level than the remaining fourteen subjects (Group A). After walking, group B had significant reductions in dominant-side ankle joint range of motion and power, suggesting lower-leg muscle fatigue, which appeared to be compensated by significantly increased non-dominant side knee and hip motions. These changes were not observed in Group A. Differences in gait parameters between Group A and B implied that some biomechanical factors might contribute to the lack of walking of some older adults

    Efficient X-ray CT-based numerical computations of structural and mass transport properties of nickel foam-based GDLs for PEFCs

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    Nickel foams are excellent candidate materials for gas diffusion layers (GDLs) for polymer electrolyte fuel cells (PEFCs) and this is due to their superior structural and transport properties. A highly computationally-efficient framework has been developed to not only estimate the key structural and mass transport properties but also to examine the multi-dimensional uniformity and/or the isotropy of these properties. Specifically, multiple two-dimensional X-ray CT images and/or numerical models have been used to computationally determine the porosity, the tortuosity, the pore size distribution, the ligament thickness, the specific surface area, the gas permeability and the effective diffusivity of a typical nickel foam sample. The results show that, compared to the conventionally used carbon substrate, the nickel foam sample demonstrate a high degree of uniformity and isotropy and that it has superior structural and mass transport properties, thus underpinning its candidacy as a GDL material for PEFCs. All the computationally-estimated properties, which were found to be consistent with the corresponding literature data, have been presented and thoroughly discussed

    Differential expression of mycobacterial antigen MPT64, apoptosis and inflammatory markers in multinucleated giant cells and epithelioid cells in granulomas caused by Mycobacterium tuberculosis

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    The development of granulomas is a major histopathological feature of tuberculosis. Very little information is available concerning the physiology and functions of different cell types in the tuberculous granulomas. The aim of this study was to compare the epithelioid cells (ECs) and multinucleated giant cells (MGCs) in the granulomas caused by Mycobacterium tuberculosis complex organisms. Lymph node biopsies from 30 cases of lymphadenitis were studied for expression of the secreted mycobacterial protein MPT64, caspase 3 as a marker of apoptosis, apoptosis-related proteins (Fas Ligand, Fas and Bax) and inflammatory cytokines (interleukin-10, transforming growth factor-ÎČ (TGF-ÎČ), tumour necrosis factor-α and interferon-Îł) by immunohistochemistry. MGCs more often contained M. tuberculosis secretory antigen MPT64 (p < 0.001) and expressed more TGF-ÎČ (p = 0.004) than ECs. The total number of apoptotic MGCs was higher than the number of apoptotic ECs (p = 0.04). Interestingly, there was a significant negative correlation between apoptosis and MPT64 expression in MGCs (r = −0.569, p = 0.003), but not in ECs, implying that the heavy antigen load would lead to inhibition of apoptosis in these cells. When compared with ECs, higher percentage of MGCs expressed Fas Ligand and Fas (p < 0.004). The role of MGCs may thus be different from surrounding ECs and these cells by virtue of higher mycobacterial antigen load, more TGF-ÎČ and reduced apoptosis may contribute towards persistence of infection

    Evaluation of the properties of modified local asphalt binder by using styrene butadiene rubber (SBR) or low-density polyethylene (LDPE)

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    The influence of styrene butadiene rubber (SBR) or low-density polyethylene (LDPE) polymers on the characteristics of local asphalt binder was analyzed to characterize the rheological properties. The results indicated that the SBR or LDPE increased the softening point. The softening point was enhanced by around 35% when 9% of SBR was used in comparison to the unmodified asphalt, while there was a 15% increment when LDPE was used. The results also indicated that the SBR or LDPE decreased the penetration rate. The penetration decreases by around 36% when 9% of SBR is used compared to the neat asphalt, while a significant increment was 89% when 9% of LDPE is used. Additionally, when 9% SBR was employed, the ductility of the asphalt binder rose by roughly 73%, but 64% less ductility was seen when 9% LDPE was utilized. Finally, the addition of the additive has improved the penetration index, thus reducing the temperature sensitivity. Due to said above, SBR and LDPE are practical and promising modifiers that will be useful in enhancing the performance of the asphalt binder straightforwardly and efficiently

    Valuing the value: An affordances perspective on new models in the electricity market

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    Prosumers can actively participate in electricity markets through new market models. Peer-to-peer, community self-consumption, and transactive energy are the three market models which are said to complement traditional electricity markets, enabling prosumers to create and capture value. To date, however, the characteristics of these models and incentivisation opportunities for prosumers cannot be easily distilled. Here, we propose a framework to distinguish between these market models based on involved parties (peers, communities, and grid operators) and traded commodities (electricity and flexibility). Furthermore, we compare the capacity of the different models in value generation for and by prosumers, which extend beyond financial benefits, by differentiation. In doing so, we systematically draw out the value generation potential in the dynamic between market models' capacities and prosumers business models. In doing so, a larger number of prosumers can be engaged and empowered in becoming active market actors, stimulating the ongoing energy transition towards achieving sustainability goals

    Time-dependent asymptotic behavior of the solution for evolution equation with linear memory

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    In this article, by using the operator decomposition technique, we discuss the existence of a time-dependent global attractor for a nonlinear evolution equation with linear memory within the theory of time-dependent space. Furthermore, the regularity and asymptotic structure of the time-dependent attractor are proved, which means that the time-dependent attractor of the evolution equation converges to the attractor of the limit wave equation when the coefficient Δ(t)→0 \varepsilon(t)\rightarrow0 as t→∞ t\rightarrow \infty
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