Relatively little experimental evidence is available regarding how ecological resistance and propagule density interact in their effects on the establishment of invasive exotic species. We examined the independent and interactive effects of neighbour cover (biotic resistance), winter vs. spring water addition (abiotic resistance) and seed density on the invasion of the European perennial grass ...

[1] Isotopic hydrograph separation (IHS) to define sources of event and preevent water during hydrological episodes has greatly improved the understanding of water, solute, and contaminant transport to streams during recent decades. However, the large variation in snowmelt isotopic composition, caused by fractionation during melting, has impeded an accurate separation of streamflow during sprin...

The purpose of this study was to determine and compare the performances of conventional and heat pump systems for energy and water conservation in open and confined greenhouse systems. Conventional gas furnaces and evaporative cooling, respectively, provided heating and cooling in the conventional system. In the heat pump systems, gas-fired heat pump units provided both heating and cooling. The...

In the western United States, over half of the water supply is derived from mountain snowmelt, with the snow acting as a natural reservoir, delaying runoff and providing runoff in the spring and summer when it is needed most. Interannual variability of both the magnitude and timing of spring runoff is tremendous, and western states have developed extensive reservoir systems to store water from ...

Background & Aims of the Study: Corrosion and scaling play undesirable effects on transmission and distribution system of drinking water. The aim of this study was to assess the corrosion and scaling potential of drinking water resources in Babol city, Iran. Materials and Methods: Totally, 54 water samples were collected from 27 wells in spring and autumn. Calcium har...

A bedload trap in the riverbed provided direct quantitative measurement of debris-transport rate in the East Fork River, Wyoming, a basin of 466 km(2) drainage area. Traction load moves only during the spring snow melt season. Data collected in three spring runoff seasons during which a peak flow of 45 m(3)/s occurred showed that transport rate is correlated with power expenditure of the flowin...

The Antarctic plateau provides superb sites for infrared astronomy, a result of the combination of low temperatures, low levels of precipitable water vapor, high altitude, and atmospheric stability. We have undertaken measurements of the sky background from 1 to 5 km at the South Pole, using a single channel InSb spectrometer, the Infrared Photometer Spectrometer (IRPS), during the winter (dark...

background trihalomethanes (thms) are major group of chlorinated by products, potentially hazardous and carcinogenicity of these compounds was recognized. the purpose of this study was survey on thms concentration in ahvaz drinking water. material and methods a descriptive cross-sectional study was based on 36-week sampling program during the winter, spring and summer of 2011 in water distribut...