744 research outputs found

    Primary osteoblast-like cells from patients with end-stage kidney disease reflect gene expression, proliferation, and mineralization characteristics ex vivo.

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    Osteocytes regulate bone turnover and mineralization in chronic kidney disease. As osteocytes are derived from osteoblasts, alterations in osteoblast function may regulate osteoblast maturation, osteocytic transition, bone turnover, and skeletal mineralization. Thus, primary osteoblast-like cells were cultured from bone chips obtained from 24 pediatric ESKD patients. RNA expression in cultured cells was compared with RNA expression in cells from healthy individuals, to RNA expression in the bone core itself, and to parameters of bone histomorphometry. Proliferation and mineralization rates of patient cells were compared with rates in healthy control cells. Associations were observed between bone osteoid accumulation, as assessed by bone histomorphometry, and bone core RNA expression of osterix, matrix gla protein, parathyroid hormone receptor 1, and RANKL. Gene expression of osteoblast markers was increased in cells from ESKD patients and signaling genes including Cyp24A1, Cyp27B1, VDR, and NHERF1 correlated between cells and bone cores. Cells from patients with high turnover renal osteodystrophy proliferated more rapidly and mineralized more slowly than did cells from healthy controls. Thus, primary osteoblasts obtained from patients with ESKD retain changes in gene expression ex vivo that are also observed in bone core specimens. Evaluation of these cells in vitro may provide further insights into the abnormal bone biology that persists, despite current therapies, in patients with ESKD

    Yield Response of Tolerant and Susceptible Soybean to the Soybean Aphid

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    Soybean aphid, Aphis glycines (Hemiptera: Aphididae), is the most economically important soybean [Glycine max (L.) Merr.] pest of North America. Multiple studies have identified soybean expressing antibiosis and/or antixenosis; however, soybean tolerance remains underexplored. Tolerance to soybean aphid injury was previously identified in soybean KS4202. This research examined the yield response of KS4202 infested with soybean aphid at specific plant stages and identified at what plant stage tolerance initiates. A preliminary study evaluated the yield parameters of the tolerant genotype at low (4000– 5500 cumulative aphid-days [CAD]) and high aphid pressure (7500–8500 CAD) at different growth stages (V1, V3, and R1). A second study compared the yield response of the tolerant and a susceptible genotype (K03-4686) at both V1 and V3 stages. In addition, low and high aphid pressure increased to 9,000 to 12,000 and 18,000 to 25,000 for V1 and V3 stages, respectively. Preliminary evaluations indicated that the yield parameters of the tolerant genotype infested at V3 and R1 were not significantly different from the respective controls. Conversely, plants were unable to compensate for of high aphid pressure at the V1 stage. In study 2, high aphid pressure negatively influenced yield of both tolerant and susceptible V1-plants infested, although the tolerant genotype compensated for low aphid pressure. Aphid pressures applied at the V3 stage did not influence the yield parameters of tolerant genotype; however, both aphid pressures were detrimental to the susceptible genotype. Tolerance in KS4202 begins as early as V3, and maintains as plants mature

    The North Atlantic oscillation and European vegetation dynamics

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    The relationship between vegetation greenness and the North Atlantic Oscillation (NAO) is assessed over Europe. The study covers the 21-year period from 1982 to 2002 and is based on monthly composites of the Normalised Difference Vegetation Index (NDVI) and Brightness Temperature from the Global Inventory Monitoring and Modelling System (GIMMS) as well as on monthly precipitation from the Global Precipitation Climatology Centre (GPCC). A systematic analysis is first performed of point correlation fields over the 21-year period between the winter NAO index and spring and summer NDVI, followed by an assessment of the vegetation response to precipitation and temperature conditions in winter, over two contrasting regions, namely the Iberian Peninsula and Northeastern Europe. Finally, the impact of NAO on vegetation dynamics over the two regions is evaluated by studying the corresponding annual cycles of NDVI and comparing their behaviour for years associated with opposite NAO phases. Over the Iberian Peninsula there is strong evidence that positive (negative) values of winter NAO induce low (high) vegetation activity in the following spring and summer seasons. This feature is mainly associated with the impact of NAO on winter precipitation, together with the strong dependence of spring and summer NDVI on water availability during the previous winter. Northeastern Europe shows a different behaviour, with positive (negative) values of winter NAO inducing high (low) values of NDVI in spring, but low (high) values of NDVI in summer. This behaviour mainly results from the strong impact of NAO on winter temperature, associated with the critical dependence of vegetation growth on the combined effect of warm conditions and water availability during the winter seaso

    Perspectives of PV Microgeneration in Brazil: A Proposition of Regulation Enhancement Methodology

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    The solar photovoltaic (PV) generation is disseminating on multiple kinds of sites due to the energy market liberalization, the renewable energy sources subsidies policy, the decreasing of acquisition costs and the adaptability to different installation conditions. These factors allowed the growth of PV generation, especially in the distributed generation (DG) segment. Meanwhile, the development of a legal and regulatory apparatus became mandatory to assure benefits to DG-adopters, without causing damages to the utility grid, preventing technical failures and eventual excessive pricing to non-adopters. As the technology innovations impose new possibilities and the number of adopters grows exponentially, the challenges become more visible and a regulation update, urgent. In this context, this paper aims to review the current pricing model for DG in Brazil, focusing on PV microgeneration, and to propose a methodology based on the Delphi Method to enhance the most critical topics of the on-going regulation

    Design and construction of a didactic standalone photovoltaic plant

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    This paper proposes the design and construction of a standalone didactic photovoltaic (PV) plant. The system components are available as a didactic kit to the students of the Federal Institute of Education, Science and Technology of Ceará (IFCE), Brazil. Thus, contributing to the teaching-learning process and providing a system to be used in future researches. In addition, the system was designed for supplying electricity to the lighting circuit of the Energy Processing Laboratory, located at IFCE Fortaleza Campus. The PV system developed during the work has an autonomy of 900 Ah and the total installed power of 840 Wp. Using a data capture system, a generation generated by the PV microgeneration was registered in operation up to 647 W

    Distribuição de aranhas de teia de sub-bosque ao longo de uma área de contato entre floresta de Araucaria e plantação de Pinus no sul do Brasil

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    In southern Brazil, the native Araucaria forest has been tremendously cut down, which created a mosaic landscape with patches of original forest and other land uses. The Floresta Nacional de São Francisco de Paula encompasses a mosaic landscape comprised of the Araucaria forest, Araucaria plantations, Pinus and Eucalyptus plantations. This study’s intention was to assess the richness and abundance of understorey web building spiders along an interface zone between an Araucaria and a Pinus patch. Spiders and other arthropods were collected by beating the vegetation inside five random plots, along five long transects parallels to the edge: one at the edge, two others 10 m and 30 m inside each patch. A randomization test was done to analyze differences in richness and abundance among distances between patches. Linear regressions were done to assess influence of the abundance of potential prey on spider richness and abundance. A total of 161 web building spiders were collected, divided in 35 morphospecies and 7 families. Four morphospecies represented around 42% of abundance. The higher abundance was of Theridiidae (17 species), followed by Araneidae (11). Richness and abundance of understorey spiders did not differ among the distances, showing presence of connectivity across the understorey vegetation of patches. Arthropod numbers positively influenced the abundance and richness of spiders. Management practices applied in this Reserve, which are selective cutting and long periods of rotations, seem to provide the growth of dense understorey vegetation along the ecotone resulting in adequate resources to support spider diversity. Key words: edge effect, ecotone, Atlantic Forest, forest management.A floresta de Araucaria tem sido intensivamente impactada, o que possibilitou a criação de mosaicos da paisagem com manchas da floresta original e outros usos da terra. A Floresta Nacional de São Francisco de Paula, RS, abriga um mosaico composto da floresta de Araucaria e plantações de Araucaria, Pinus e Eucalyptus. Este estudo visou avaliar a riqueza e abundância das assembléias de aranhas de teia de sub-bosque ao longo de uma área de contato entre uma mancha de Araucaria e outra de Pinus. Aranhas e outros artrópodes foram coletados com guarda-chuva entomológico em cinco parcelas ao longo de cinco transectos paralelos à borda das manchas: uma na borda, duas outras a 10 m e a 30 m em cada mancha. Diferenças na riqueza e na abundância ao longo das distâncias foram analisadas por um teste de aleatorização. Foram realizadas regressões lineares para avaliar a influência da abundância de presas potenciais sobre a abundância e riqueza de aranhas de teia. Um total de 161 aranhas foi coletado (35 morfoespécies e 7 famílias). Quatro morfoespécies representaram em torno de 42% da abundância. A família mais rica foi Theridiidae (17 espécies), seguida de Araneidae (11). A riqueza e a abundância de aranhas não variaram entre as distâncias, mostrando que há conectividade entre as vegetações dos sub-bosques. A abundância de presas potenciais influenciou positivamente a abundância e a riqueza de aranhas de teia. Presume-se que o manejo executado na reserva, com corte seletivo e longo tempo de rotação, possibilite o crescimento do sub-bosque de Pinus, proporcionando recursos adequados para a manutenção da diversidade de aranhas. Palavras-chave: efeito de borda, ecótono, Mata Atlântica, manejo de florestas

    THE ANKLE-HIP TRANSVERSE PLANE COUPLING DURING THE STANCE PHASE OF NORMAL WALKING

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    The aim of this study was to investigate the strength and features of a possibly existent ankle-hip transverse plane coupling during the stance of walking. Fifteen healthy volunteers walked on a 10m walkway in their natural speed using sandals. Kinematic data were obtained with a 3-dimensional motion analysis system. Calculation of the cross-correlation (r=-0.78) indicated a strong ankle-hip coupling, with ankle external rotation (foot pronation) coupled with hip internal rotation, and ankle internal rotation (foot supination) coupled with hip external rotation. Vector coding technique (Φ=41.01°) showed that ankle and hip joints present similar displacement magnitudes. The results agree with suggestions of ankle-hip transverse plane interdependency and an important kinetic energy transmission between the shank and thigh in this plane of movement

    EFFECTS OF SIMULATING FOREFOOT VARISM INCREASES ON LOWER EXTREMITY KINEMATICS DURING THE STANCE PHASE OF WALKING

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    This study investigates the effects of simulating forefoot varism increases on lower extremity kinematics during the stance phase. Sixteen volunteers walked on a walkway in three conditions: wearing flat sandals; wearing a 5º and a 10º laterally wedged sandal. Data were obtained with a 3-D motion analysis system. The variables analyzed were: subtalar eversion/inversion; shank internal/external rotation; knee internal/external rotation; hip internal/external rotation. The simulations of 5º and 10º increases in forefoot varism increased subtalar pronation (P≤.007) and the simulation of 10º increased internal rotation of the shank in relation to the pelvis and of the hip (P=.001). The results suggest that forefoot varism can lead to kinematic patterns related to the occurrence of overuse injuries

    Embedded System for Real Color Composition in Experimental Physics

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    Software can be considered educational when properly contextualized in a relationship of teaching and learning. This paper describes an embedded system and an educational software developed and applied in experimental physics to real and virtual colors composition. The educational system developed allows student interaction by voice commands, which makes the assimilation process of red/green/blue (RGB) color formation concepts more didactic and playful. The application of educational software in experiments also allows to verify, in real time, the influence of programs change on the physical phenomena and stimulates the logical reasoning development and consequently the autonomy of the students, to the measure that can raise hypothesis, make modifications in the programming and take off conclusions from the practical results obtained

    The potential of satellite data to study individual wildfire events

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    Geophysical Research Abstract of EGU General Assembly 2014, held 27 April - 2 May, 2014 in Vienna, Austria
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