The Scientific World Journal

https://www.hindawi.com/journals/tswj/

List of Papers (Total 3,303)

Limitations of Improved Nitrogen Management to Reduce Nitrate Leaching and Increase Use Efficiency

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing...

Multiple Receptor Subtypes for the CGRP Super-Family

Molecular evidence for the existence of multiple receptors for CGRP has been rather difficult to obtain. Over 10 years after suggesting the existence of at least two classes (CGRP1 and CGRP2) of CGRP receptors on the basis of pharmacological data[1], molecular data on the CGRP2 receptor subtype are still lacking as well as potent and selective antagonists. The situation is...

Stem Cell Quandary Quashes Research, Smithsonian Secretary Backs Down from CRC Closure - and Welcome Back to Star Wars

Nature leads this week with a story about how questions surrounding stem cell research have thrown a funding agency and the German government into the boxing ring. The contested overhaul of the U.S. Smithsonian Institution tops the news this week in Science.

Why Homeodynamics, Not Homeostasis?

Ideas of homeostasis derive from the concept of the organism as an open system. These ideas can be traced back to Heraclitus. Hopkins, Bernard, Hill, Cannon, Weiner and von Bertalanffy developed further the mechanistic basis of turnover of biological components, and Schoenheimer and Rittenberg were pioneers of experimental approaches to the problems of measuring pool sizes and...

Deposition of Atmospheric Nitrogen Compounds in Humid Tropical Cuba

Acid deposition, a direct effect of gaseous air pollutants, is causing widespread damage to terrestrial and aquatic ecosystems. Further, these pollutants are responsible for the corrosion of building materials and cultural objects, as well as having an impact on human health. In Cuba, main atmospheric deposition of nitrogen compounds varies from approximately 12.0 to 65.0 kg N ha...

Atmospheric Deposition of Nitrogen and Sulphur Compounds in the Czech Republic

Estimates of dry and wet deposition of nitrogen and sulphur compounds in the Czech Republic for the years 1994 and 1998 are presented. Deposition has been estimated from monitored and modeled concentrations in the atmosphere and in precipitation, where the most important acidifying compounds are sulphur diOxide, nitrogen Oxides, ammonia, and their reaction products. Measured...

Air Pollution and Forest Health: Establishing Cause and Effect in the Forest

I participated in a NATO Advanced Research Workshop titled “Effects of Air Pollution on Forest Health and Biodiversity in Forests of the Carpathian Mountains,” in Stara Lesna, Slovakia from May 22–26, 2001. Researchers from Canada, Czech Republic, Poland, Romania, Slovakia, Ukraine, and the U.S. met to present their results from a three-year cooperative study of tree health and...

Nitrogen Emission and Deposition: The European Perspective

Europe has been successful in reducing the emissions of several nitrogenous pollutants over recent decades. This is reflected in concentrations and deposition rates that have decreased for several components. Emissions of nitrogen containing gases are estimated to have decreased in Europe by 10%, 21%, and 14% for NO, NOx, and NH3, respectively, between 1990 and 1998. The main...

Evaluating Nitrogen Management Options for Reducing Nitrate Leaching from Northeast U.S. Pastures

Substantial amounts of nitrate nitrogen NO3-N can leach from intensively grazed pasture in the northeast U.S. where there is about 30 cm of groundwater recharge, annually. Management options for reducing NO3-N leaching were evaluated for this environment using the Cornell Net Carbohydrate and Protein System Model and a recently developed nitrogen leaching index. Management...

Extracellular and Intracellular Regulation of Calcium Homeostasis

An organism with an internal skeleton must accumulate calcium while maintaining body fluids at a well-regulated, constant calcium concentration. Neither calcium absorption nor excretion plays a significant regulatory role. Instead, isoionic calcium uptake and release by bone surfaces causes plasma calcium to be well regulated. Very rapid shape changes of osteoblasts and...

Derivation and Mapping of Critical Loads for Nitrogen and Trends in Their Exceedance in Germany

The term “critical load” means a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur, according to present knowledge. In the case of nitrogen, both oxidised and reduced compounds contribute to the total deposition of acidity, which exceeds critical loads in many...