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What is an erg in a desert?
erg, also called Sand Sea, in a desert region, area of large accumulation of sand, generally in the bottom of a huge basin in which a former river piled up alluvium. Ergs are areas of actively shifting dunes, “fossilized” dunes, or extensive sand sheets. The sand is generally loose and is extremely difficult to cross.
What is an erg in North Africa?
THE TERM erg is the Bedouin name for a very large body of sand dominated by sand dunes. Bedouins are an African tribe of nomadic herders living in the northern SAHARA DESERT. Two equivalent English-language terms are sand sea and dune field.
How are ergs formed?
Ergs are formed when sand from abundant sources move downwind and build up into humongous dunes and its movement is slowed down or halted by geological barriers to the flow of wind or by concurring wind flow.
What is a erg?
The electroretinogram (ERG) is a diagnostic test that measures the electrical activity of the retina in response to a light stimulus. The ERG arises from currents generated directly by retinal neurons in combination with contributions from retinal glia.
What are ergs and hamadas?
Hamada is related to desert pavement (known variously as reg, serir, gibber or saï), which occurs as stony plains or depressions covered with gravels or boulders, rather than as highland plateaus. Hamadas exist in contrast to ergs, which are large areas of shifting sand dunes.
Which desert has the largest concentration of ergs?
The world’s largest erg today is the Rub’al Khali (Empty Quarter), which covers more than 650,000 km2 in the southern Arabian Peninsula with vast expanses of sand dunes exceeding 250 m in height.
Is there dirt under sand?
No. Sand is not dirt or made from dirt! Many people assume sand is dirt and the geologist in me begs to differ. The confusion stems from the fact that the basic ingredients of dirt are; clay, silt, loam, and sand with the percentage of each varying by location.
What does ERG stand for?
employee resource group
It’s an acronym you should know. ERG stands for employee resource group. Other lesser used terms include affinity groups or business networking groups. Current groups offer much more than mere professional networking opportunities. ERGs can be found in 90\% of Fortune 500 companies.
What is an erg at work?
Employee Resource Groups are voluntary, employee-led groups whose aim is to foster a diverse, inclusive workplace aligned with the organizations they serve. They usually led and participated in by employees who share a characteristic, whether it’s gender, ethnicity, religious affiliation, lifestyle, or interest.
What is a pattern ERG?
The pattern electroretinogram (PERG) is an electrophysiologic ophthalmologic test that provides non-invasive objective, quantitative measurement of central retinal function. It objectively measures functional loss and recovery.
What for ERG is used?
2. The electroretinogram ERG. The global or full-field electroretinogram (ERG) is a mass electrical response of the retina to photic stimulation. The ERG is a test used worldwide to assess the status of the retina in eye diseases in human patients and in laboratory animals used as models of retinal disease.
What desert has seas of sand called ergs?
the Sahara Desert
The Grand Erg Oriental (English: ‘Great Eastern Sand Sea’) is a large erg or “field of sand dunes” in the Sahara Desert.