We examined individual and interactive effects of two stressors—nutrients (nitrogen [N] and phosphorus [P]) and trace elements (a mix of arsenic [As], copper [Cu], and cadmium [Cd], and in a second experiment also zinc [Zn] and nickel [Ni])—on phytoplankton of the mesohaline Patuxent River, a tributary of Chesapeake Bay. Experiments were conducted in twenty 1-m3 mesocosms. Four mesocosm runs us...

Aguirre, C.G., Madani, A., Mohtar, R. and Haghighi, K. 2007. Deterministic finite element solution of unsteady flow and transport through porous media: Model verification. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada 49: 1.1 1.9. A deterministic finite element solution to predict water flow and nutrient movement through porous media was developed and implemented using Visu...

Among factors affecting hydroponic production systems, the nutrient solution is considered to be one of the most important determining factors of crop yield and quality. This chapter aims to explain aspects related to plant nutrition and its effects on production of hydroponic crops, considering basic aspects such as nutrient solutions and their development through the years; components of nutr...

Within the central nervous system (CNS), the hypothalamus senses and integrates information on the nutrient state of the body. However, the molecular mechanisms translating nutrient sensing into changes in gene expression and, ultimately, nutrient intake remain unclear. A crucial function for the cyclic AMP-response element binding protein (CREB) co-activator CREB-regulated transcription co-act...

Previous studies have attempted to link foliar resorption of nitrogen and phosphorus to their. respective availabilities in soil, with mixed results. Based on resource optimization theory, we hypothesized that the foliar resorption of one element could be driven by the availability of another element. We tested various measures of soil N and P as predictors of N and P resorption in six tree spe...

Mineral element concentrations are presented in leaf and bark material from six woody species growing at a single site on the subantarctic Auckland Islands. Foliar total mineral element concentrations range from 5.81% (Olearia lyallii) to 2.71 % (Dracophyllum longifolium), the lowest concentrations occurring in slow growing species tolerant of nutrient-poor soils. The browse preference of intro...

The nutrient quality of the diet has been shown repeatedly to be a significant factor in modifying the response of man and animals to toxic element exposure. Deficiencies of several essential nutrients have been shown to exacerbate the effects of cadmium and supplements of such nutrients have been shown to ameliorate the toxicity. Thus the effects of exposure to a toxic element, such as cadmium...

The nicotinamide adenine dinucleotide (NAD(+))-dependent deacetylase SIRT1 is a major metabolic regulator activated by energy stresses such as fasting or calorie restriction. SIRT1 activation during fasting not only relies on the increase in the NAD(+)/NADH ratio caused by energy deprivation but also involves an upregulation of SIRT1 mRNA and protein levels in various metabolic tissues. We demo...

Manganese is a naturally occurring element and an essential nutrient. Comprising approximately 0.1% of the earth’s crust, it is the twelfth most abundant element and the fifth most abundant metal. Manganese does not exist in nature as an elemental form, but is found mainly as oxides, carbonates, and silicates in over 100 minerals with pyrolusite (manganese dioxide) as the most common naturally-...