نتایج جستجو برای: nutrient transport
تعداد نتایج: 338787 فیلتر نتایج به سال:
Maternal obesity during pregnancy is rising and is associated with increased risk of developing gestational diabetes mellitus (GDM), defined as glucose intolerance first diagnosed in pregnancy (1). Fetal growth is determined by the maternal nutrient supply and placental nutrient transfer capacity. GDM-complicated pregnancies are more likely to be complicated by fetal overgrowth or excess adipos...
Fermentation pathways have been elucidated for predominant ruminal bacteria, but information is limited concerning the specific transport mechanisms used by these microorganisms for C, energy, and N sources. In addition, it is possible that changes in ruminal environmental conditions could affect transport activity. Five carrier-mediated soluble nutrient transport mechanisms have been identifie...
This study documents the changes in nutrient fluxes associated with internal tidal bores arriving on Florida Keys coral reefs and points to biological use of subthermocline nitrate brought onshore by this mechanism. Internal bores on Conch Reef, Florida Keys, are associated with concentrations of 1.0–4.0 mmol L21 nitrate (NO ) and 0.1–0.3 3 mmol L21 soluble reactive phosphate (SRP) and onshore ...
A discussion of the effects of nutrients on springs biota and ecosystems of necessity requires an understanding of the manner and mechanism of nutrient delivery. Moreover, as evidence accumulates for particular consequences of nutrient and contaminant loading, understanding how those loads can be attenuated is crucial. This chapter focuses on nutrient loading to springsheds, with an emphasis on...
Uptake of nutrients into cells is essential to life and occurs in all organisms at the expense of energy. Whereas in most prokaryotic and simple eukaryotic cells electrochemical transmembrane proton gradients provide the central driving force for nutrient uptake, in higher eukaryotes it is more frequently coupled to sodium movement along the transmembrane sodium gradient, occurs via uniport mec...
This study aims at the quantification of possible future nutrient loads into Lake Peipsi/Chudskoe under different economic development scenarios. This drainage basin is on the borders of Russia, Estonia and Latvia. The sudden disintegration of the Soviet Union in 1991 caused a collapse of agricultural economy, and consequently, a substantial decrease of diffuse and point-source nutrient emissio...
Relations between riverine export (load) of total nitrogen (N) and total phosphorus (P) from 133 large agricultural watersheds in the United States and factors affecting nutrient transport were evaluated using empirical regression models. After controlling for anthropogenic inputs and other landscape factors affecting nutrient transport-such as runoff, precipitation, slope, number of reservoirs...
Intrauterine growth restriction refers to the inability of the fetus to reach its genetically determined potential size. Fetal growth restriction affects approximately 5-15% of all pregnancies in the United States and Europe. In developing countries the occurrence varies widely between 10 and 55%, impacting about 30 million newborns per year. Besides having high perinatal mortality rates these ...
The placement of stiff‐stemmed grass hedges on the contour along a hillslope has been shown to decrease nutrient transport in runoff. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha-1 to a s...
The description of phytoplankton growth and nutrient acquisition plays a pivotal role in affecting the performance of plankton ecosystem models. A comparison was made between the behaviour of multi-nutrient phytoplankton models with alternative descriptions of the relationships between the nutrient:C quota and growth rate (m) and for the control of the transport of the non-limiting nutrient. Us...
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