The Experts below are selected from a list of 611700 Experts worldwide ranked by ideXlab platform
Armin Kurtz - One of the best experts on this subject based on the ideXlab platform.
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Control of the renal renin system by Local Factors
Kidney International, 1998Co-Authors: Charlotte Wagner, Boye L. Jensen, Bernhard K. Krämer, Armin KurtzAbstract:Control of the renal renin system by Local Factors. Local Factors, such as prostaglandins (PGs), nitric oxide (NO), and endothelins (ETs), produced in the immediate vicinity of juxtaglomerular (JG) cells can exert significant effects on renin secretion and renin gene expression. PGE2, as the main renotubular PG, and PGI2, as the main endothelial prostanoid, both stimulate renin secretion and renin gene expression by activating cAMP formation in JG cells. Although the direct effect of NO on JG cells is less clear, its overall effect in vivo seems to be to stimulate the renin system. Evidence is emerging that stimulation by NO is related to the cAMP pathway, and cGMP-induced inhibition of cAMP-phosphodiesterase III (PDE-III) may mediate this effect. ETs, on the other hand, appear to inhibit the renin system, in particular in those pathways activated by cAMP, acting via Ca2+- and protein kinase C-related mechanisms. There is increasing evidence that both NO and PGs could be involved in the physiological regulatory mechanisms by which salt intake affects the renin system.
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Control of the renal renin system by Local Factors.
Kidney international. Supplement, 1998Co-Authors: Charlotte Wagner, Boye L. Jensen, Bernhard K. Krämer, Armin KurtzAbstract:Local Factors, such as prostaglandins (PGs), nitric oxide (NO), and endothelins (ETs), produced in the immediate vicinity of juxtaglomerular (JG) cells can exert significant effects on renin secretion and renin gene expression. PGE2, as the main renotubular PG, and PGI2, as the main endothelial prostanoid, both stimulate renin secretion and renin gene expression by activating cAMP formation in JG cells. Although the direct effect of NO on JG cells is less clear, its overall effect in vivo seems to be to stimulate the renin system. Evidence is emerging that stimulation by NO is related to the cAMP pathway, and cGMP-induced inhibition of cAMP-phosphodiesterase III (PDE-III) may mediate this effect. ETs, on the other hand, appear to inhibit the renin system, in particular in those pathways activated by cAMP, acting via Ca2+- and protein kinase C-related mechanisms. There is increasing evidence that both NO and PGs could be involved in the physiological regulatory mechanisms by which salt intake affects the renin system.
Bruno Mary - One of the best experts on this subject based on the ideXlab platform.
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Using a crop model to account for the effects of Local Factors on the LCA of sugar beet ethanol in Picardy region, France
International Journal of Life Cycle Assessment, 2013Co-Authors: Cécile Bessou, Benoit Gabrielle, Simon Lehuger, Bruno MaryAbstract:The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce Local results taking into account the Local soil, climatic and agricultural management Factors. Methods We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for Local Factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0. Results Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in Local conditions and management Factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band. Conclusions Although the crop model made it possible to take Local Factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.
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Using a crop model to account for the effects of Local Factors on the LCA of sugar beet ethanol in Picardy region, France
The International Journal of Life Cycle Assessment, 2013Co-Authors: Cécile Bessou, Benoit Gabrielle, Simon Lehuger, Bruno MaryAbstract:Purpose The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce Local results taking into account the Local soil, climatic and agricultural management Factors. Methods We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for Local Factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0. Results Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in Local conditions and management Factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band. Conclusions Although the crop model made it possible to take Local Factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.
Charlotte Wagner - One of the best experts on this subject based on the ideXlab platform.
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Control of the renal renin system by Local Factors
Kidney International, 1998Co-Authors: Charlotte Wagner, Boye L. Jensen, Bernhard K. Krämer, Armin KurtzAbstract:Control of the renal renin system by Local Factors. Local Factors, such as prostaglandins (PGs), nitric oxide (NO), and endothelins (ETs), produced in the immediate vicinity of juxtaglomerular (JG) cells can exert significant effects on renin secretion and renin gene expression. PGE2, as the main renotubular PG, and PGI2, as the main endothelial prostanoid, both stimulate renin secretion and renin gene expression by activating cAMP formation in JG cells. Although the direct effect of NO on JG cells is less clear, its overall effect in vivo seems to be to stimulate the renin system. Evidence is emerging that stimulation by NO is related to the cAMP pathway, and cGMP-induced inhibition of cAMP-phosphodiesterase III (PDE-III) may mediate this effect. ETs, on the other hand, appear to inhibit the renin system, in particular in those pathways activated by cAMP, acting via Ca2+- and protein kinase C-related mechanisms. There is increasing evidence that both NO and PGs could be involved in the physiological regulatory mechanisms by which salt intake affects the renin system.
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Control of the renal renin system by Local Factors.
Kidney international. Supplement, 1998Co-Authors: Charlotte Wagner, Boye L. Jensen, Bernhard K. Krämer, Armin KurtzAbstract:Local Factors, such as prostaglandins (PGs), nitric oxide (NO), and endothelins (ETs), produced in the immediate vicinity of juxtaglomerular (JG) cells can exert significant effects on renin secretion and renin gene expression. PGE2, as the main renotubular PG, and PGI2, as the main endothelial prostanoid, both stimulate renin secretion and renin gene expression by activating cAMP formation in JG cells. Although the direct effect of NO on JG cells is less clear, its overall effect in vivo seems to be to stimulate the renin system. Evidence is emerging that stimulation by NO is related to the cAMP pathway, and cGMP-induced inhibition of cAMP-phosphodiesterase III (PDE-III) may mediate this effect. ETs, on the other hand, appear to inhibit the renin system, in particular in those pathways activated by cAMP, acting via Ca2+- and protein kinase C-related mechanisms. There is increasing evidence that both NO and PGs could be involved in the physiological regulatory mechanisms by which salt intake affects the renin system.
Gentile Francesco Ficetola - One of the best experts on this subject based on the ideXlab platform.
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Ecogeographic variation of body size in the spectacled salamanders (Salamandrina): influence of genetic structure and Local Factors
Journal of Biogeography, 2010Co-Authors: Antonio Romano, Gentile Francesco FicetolaAbstract:Aim The patterns and causes of ecogeographical body size variation in ectotherms remain controversial. In amphibians, recent genetic studies are leading to the discovery of many cryptic species. We analysed the relationships between body size and climate for a salamander (Salamandrina) that was recently separated into two sibling species, to evaluate how ignoring interspecific and intraspecific genetic structure may affect the conclusions of ecogeographical studies. We also considered the potential effects of Factors acting at a Local scale. Location Thirty-four populations covering the whole range of Salamandrina, which is endemic to peninsular Italy. Methods We pooled original data and data from the literature to obtain information on the snout–vent length (SVL) of 3850 Salamandrina females; we obtained high-resolution climatic data from the sampled Localities. We used an information-theoretic approach to evaluate the roles of climate, genetic features (mitochondrial haplogroup identity) and characteristics of aquatic oviposition sites. We repeated our analyses three times: in the first analysis we ignored genetic data on intraspecific and interspecific variation; in the second one we considered the recently discovered differences between the two sibling species; in the third one we included information on intraspecific genetic structure within Salamandrina perspicillata (for Salamandrina terdigitata the sample size was too small to perform intraspecific analyses). Results If genetic information was ignored, our analysis suggested the existence of a relationship between SVL and climatic variables, with populations of large body size in areas with high precipitation and high thermal range. If species identity was included in the analysis, the role of climatic features was much weaker. When intraspecific genetic differences were also considered, no climatic feature had an effect. In all analyses, Local Factors were important and explained a large proportion of the variation; populations spawning in still water had a larger body size. Main conclusions An imperfect knowledge of species boundaries, or overlooking the intraspecific genetic variation can strongly affect the results of analyses of body size variation. Furthermore, Local Factors can be more important than the large-scale parameters traditionally considered, particularly in species with a small range.
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the spectacled salamanders (Salamandrina): influence of genetic structure and Local Factors
2010Co-Authors: Antonio Romano, Gentile Francesco FicetolaAbstract:Aim The patterns and causes of ecogeographical body size variation in ectotherms remain controversial. In amphibians, recent genetic studies are leading to the discovery of many cryptic species. We analysed the relationships between body size and climate for a salamander (Salamandrina) that was recently separated into two sibling species, to evaluate how ignoring interspecific and intraspecific genetic structure may affect the conclusions of ecogeographical studies. We also considered the potential effects of Factors acting at a Local scale. Location Thirty-four populations covering the whole range of Salamandrina, which is endemic to peninsular Italy. Methods We pooled original data and data from the literature to obtain information on the snout–vent length (SVL) of 3850 Salamandrina females; we obtained high-resolution climatic data from the sampled Localities. We used an information-theoretic approach to evaluate the roles of climate, genetic features (mitochondrial haplogroup identity) and characteristics of aquatic oviposition sites. We repeated our analyses three times: in the first analysis we ignored genetic data on intraspecific and interspecific variation; in the second one we considered the recently discovered differences between the two sibling species; in the third one we included information on intraspecific genetic structure within Salamandrina perspicillata (for Salamandrina terdigitata the sample size was too small to perform intraspecific analyses). Results If genetic information was ignored, our analysis suggested the existence of a relationship between SVL and climatic variables, with populations of large body size in areas with high precipitation and high thermal range. If species identity was included in the analysis, the role of climatic features was much weaker. When intraspecific genetic differences were also considered, no climatic feature had an effect. In all analyses, Local Factors were important and explained a large proportion of the variation; populations spawning in still water had a larger body size. Main conclusions An imperfect knowledge of species boundaries, or overlooking the intraspecific genetic variation can strongly affect the results of analyses of body size variation. Furthermore, Local Factors can be more important than the large-scale parameters traditionally considered, particularly in species with a small range.
Cécile Bessou - One of the best experts on this subject based on the ideXlab platform.
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Using a crop model to account for the effects of Local Factors on the LCA of sugar beet ethanol in Picardy region, France
International Journal of Life Cycle Assessment, 2013Co-Authors: Cécile Bessou, Benoit Gabrielle, Simon Lehuger, Bruno MaryAbstract:The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce Local results taking into account the Local soil, climatic and agricultural management Factors. Methods We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for Local Factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0. Results Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in Local conditions and management Factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band. Conclusions Although the crop model made it possible to take Local Factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.
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Using a crop model to account for the effects of Local Factors on the LCA of sugar beet ethanol in Picardy region, France
The International Journal of Life Cycle Assessment, 2013Co-Authors: Cécile Bessou, Benoit Gabrielle, Simon Lehuger, Bruno MaryAbstract:Purpose The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce Local results taking into account the Local soil, climatic and agricultural management Factors. Methods We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for Local Factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0. Results Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in Local conditions and management Factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band. Conclusions Although the crop model made it possible to take Local Factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.
