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61.
Leandro Neves Faria Marlon Gomes Da Rocha Quirijn De Jong Van Lier Derblai Casaroli 《Plant and Soil》2010,331(1-2):299-311
Correct modeling of root water uptake partitioning over depth is an important issue in hydrological and crop growth models. Recently a physically based model to describe root water uptake was developed at single root scale and upscaled to the root system scale considering a homogeneous distribution of roots per soil layer. Root water uptake partitioning is calculated over soil layers or compartments as a function of respective soil hydraulic conditions, specifically the soil matric flux potential, root characteristics and a root system efficiency factor to compensate for within-layer root system heterogeneities. The performance of this model was tested in an experiment performed in two-compartment split-pot lysimeters with sorghum plants. The compartments were submitted to different irrigation cycles resulting in contrasting water contents over time. The root system efficiency factor was determined to be about 0.05. Release of water from roots to soil was predicted and observed on several occasions during the experiment; however, model predictions suggested root water release to occur more often and at a higher rate than observed. This may be due to not considering internal root system resistances, thus overestimating the ease with which roots can act as conductors of water. Excluding these erroneous predictions from the dataset, statistical indices show model performance to be of good quality. 相似文献
62.
Paula C. Rodríguez-Flores David Buckley Enrique Macpherson Laure Corbari Annie Machordom 《Zoologica scripta》2020,49(3):340-356
The ecology, abundance and diversity of galatheoid squat lobsters make them an ideal group to study deep-sea diversification processes. Here, we reconstructed the evolutionary and biogeographic history of Leiogalathea, a genus of circum-tropical deep-sea squat lobsters, in order to compare patterns and processes that have affected shallow-water and deep-sea squat lobster species. We first built a multilocus phylogeny and a calibrated species tree with a relaxed clock using StarBEAST2 to reconstruct evolutionary relationships and divergence times among Leiogalathea species. We used BioGeoBEARS and a DEC model, implemented in RevBayes, to reconstruct ancestral distribution ranges and the biogeographic history of the genus. Our results showed that Leiogalathea is monophyletic and comprises four main lineages; morphological homogeneity is common within and between clades, except in one; the reconstructed ancestral range of the genus is in the Atlantic and Indian oceans (Tethys). They also revealed the divergence of the Atlantic species around 25 million years ago (Ma), intense cladogenesis 15–25 Ma and low levels of speciation over the last 5 million years (Myr). The four Leiogalathea lineages showed similar patterns of speciation: allopatric speciation followed by range expansion and subsequent stasis. Leiogalathea started diversifying during the Oligocene, likely in the Tethyan. The Atlantic lineage then split from its Indo-Pacific sister group due to vicariance driven by closure of the Tethys Seaway. The Atlantic lineage is less speciose compared with the Indo-Pacific lineages, with the Tropical Southwestern Pacific being the current centre of diversity. Leiogalathea diversification coincided with cladogenetic peaks in shallow-water genera, indicating that historical biogeographic events similarly shaped the diversification and distribution of both deep-sea and shallow-water squat lobsters. 相似文献
63.
This research examines factors associated with the timing of first birth in Canada, focusing primarily on the role of women's educational attainment. Proportional hazards modelling techniques are applied to data from the 1984 Canadian Fertility Survey (CFS) in order to determine how educational attainment, estimated as close as possible to the date of first birth, influences the timing of first birth and whether the importance of this variable varies according to age cohorts. The results suggest that among a number of variables useful for distinguishing different levels of risk, educational attainment proves to be the most important predictor in the model. Education exerts a substantial positive influence on birth timing for women of all age groups. As expected, moreover, significant cohort differences are also evident, with the greatest to the smallest impact on the risk from the youngest to the oldest cohorts. These clear-cut cohort differences indicate a fundamental change in the effects of education over time, a trend most likely resulting from substantial changes in both the content and social significance of formal schooling during the past few decades. 相似文献
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66.
Alkalinity of the medium was shown to be the chief factor involved in the accumulation of oxalate by T. cinnabarina. Glutamate and aspartate are shown to lead to oxalate with this organism and with L. lepideus by dehydrogenation to α-ketoglutarate and oxaloacetate, respectively. Malate was also shown to be dehydrogenated. It is proposed that oxaloacetate may either undergo β-decarboxylation to yield CO2 and pyruvate, or splitting by coenzyme A to yield oxalate and acetylated coenzyme A. The reversal of this latter reaction is suggested as the explanation of the disappearance of oxalate from culture media. The reduction of resazurin by the dehydrogenase systems of the molds is inhibited by cyanide, indicating the participation of metal systems, such as the cytochromes. 相似文献
67.
J Daigneault G Aubin F Simard M De Braekeleer 《Human biology; an international record of research》1992,64(1):115-119
The incidence of cystic fibrosis (CF) in Saguenay-Lac-St.-Jean, a geographically isolated region of Quebec, was estimated to be 1 in 902 during the period 1975-1988. The carrier rate was calculated to be 1 in 15 inhabitants. The high incidence of CF in Saguenay-Lac-St.-Jean is probably the result of a founder effect and genetic drift for one or more mutations. Historical, demographic, and social factors also may have contributed to the high incidence. 相似文献
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69.
S D Kroll J Chen M De Vivo D J Carty A Buku R T Premont R Iyengar 《The Journal of biological chemistry》1992,267(32):23183-23188
70.
Yi-Shiang Huang Virginie Bertrand Dimitriya Bozukova Christophe Pagnoulle Christine Labrugère Edwin De Pauw Marie-Claire De Pauw-Gillet Marie-Christine Durrieu 《PloS one》2014,9(12)
Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient''s age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO. On the other hand, we have previously demonstrated that the adhesion of LECs is favored on hydrophobic compared to hydrophilic materials. By combining these two facts and contemporary knowledge in PCO development via the EMT pathway, we propose a biomimetically inspired strategy to promote LEC adhesion without de-differentiation to reduce the risk of PCO development. By surface grafting of a cell adhesion molecule (RGD peptide) onto the conventional hydrophilic acrylic IOL material, the surface-functionalized IOL can be used to reconstitute a capsule-LEC-IOL sandwich structure, which has been considered to prevent PCO formation in literature. Our results show that the innovative biomaterial improves LEC adhesion, while also exhibiting similar optical (light transmittance, optical bench) and mechanical (haptic compression force, IOL injection force) properties compared to the starting material. In addition, compared to the hydrophobic IOL material, our bioactive biomaterial exhibits similar abilities in LEC adhesion, morphology maintenance, and EMT biomarker expression, which is the crucial pathway to induce PCO. The in vitro assays suggest that this biomaterial has the potential to reduce the risk factor of PCO development. 相似文献