Monday, April 21, 2008

Physical actions in water cycle

The Physical actions in water cycle is of fives main types. They are evaporation, precipitation, infiltration, runoff, and subsurface flow.
The Evaporation is the transfer of water from the bodies of surface water into the atmosphere. This transfer requires a change in the physical nature of water from liquid to gaseous phases. Along with the evaporation, it can be counted transpiration from plants. Therefore, this transfer is sometimes referred to as evapotranspiration. 90% of atmospheric water comes from evaporation, while the left over 10% is from transpiration.

Precipitation is the atmospheric moisture that has formerly condensed to form clouds (changed from the gas phases to a liquid or solid phase), falling to the surface of the earth. This generally occurs as rainfall, but snow, hail, fog drip, and other forms participate too.
Infiltration into the ground is the transition from the surface water to the groundwater. The infiltration rate will depend upon soil or rock permeability with the other factors. Infiltrated water possibly will reach another compartment called as groundwater (i.e., an aquifer). The Ground waters tend to move slowly, so the water may perhaps return as surface water after storage within an aquifer for a period of time that can amount to thousands of years in few cases. The Water returns to the land surface at lower rise than where it infiltrated, under force of the gravity or the gravity induced pressures.
Runoff includes the variety of ways by which land surface water moves downward slope to the oceans. The Water flowing in streams and rivers can be delayed for a time in lakes. Not all precipitated water goes back to the sea as runoff; much of it evaporates before reaching the ocean or reaching an aquifer.
The Subsurface flow includes movement of water within the earth, either within the vadose zone or aquifers. After infiltrating, subsurface water can return to the surface or finally seep into the ocean.

Thursday, April 10, 2008

What do you mean by Exercise Hypertension?

The Exercise hypertension is an extreme rise in blood pressure during exercise. Many of those with work out hypertension contain spikes in systolic pressure to 250mm or greater.
In accordance with Klaus a rise in systolic blood pressure to over 200mm when exercising at 100W is 'pathological', and rises more than to over 220mm need control by apt drugs.
In the same way, in healthy individuals the reaction of the diastolic pressure to 'dynamic' exercise (walking, running) of fair intensity is to stay behind constant or to fall somewhat (due to the improved blood flow), but in few individuals a go up of 10mm or greater is found. With the exercise hypertension with the reduced capability of the most important blood vessels to change in size in response to raise blood flow and this is to be differentiated from stiffness of the blood-vessel walls, which was not found to be associated with the effect.

Wednesday, April 02, 2008


Sunflowers in the bud stage show signs of heliotropism. At break of day, the faces of most sunflowers are turned towards the east. Over the course of the day, they move to track the sun from east to west, while at night they return to an eastward orientation. This movement is performed by motor cells in the pulvinus, a bendable segment of the stem just below the bud. As the bud stage ends, the stem stiffens and the blooming stage is reached.Sunflowers in the blossoming stage are not heliotropic anymore. The stem has frozen, normally in an eastward orientation. The stem and leaves lose their green color.The wild sunflower naturally does not turn toward the sun; its flowering heads may face many directions when mature. However, the leaves typically exhibit some heliotropism.