They are huge areas which have been swept by winds for so many centuries that there is no soil left, but only deep bare ridges fifty or sixty yards apart with ravines between them thirty or forty feet deep and the only thing that moves is a scuttling layer of sand.

This is a phenomenon familiar to all radio listeners, resulting from reflection of skywave signals at night from the ionized layer in the upper atmosphere known as the ionosphere.

Thermoforming the laminate and then sanding away the top layer is a quick and economical way to produce a two-color sign.

The Af layers are stacked normal to the ( 111 ) axis with the lower oxygens of one layer directly above the upper oxygens of the neighboring lower layer, in such a manner that the repeat is every three layers.

The progeny feeds on a skin layer that is specially developed by the adult.

The ovum is at first rigidly held but in fertilised eggs, the innermost layer liquefies and allows the embryo to move freely.

Each course is laid the whole length of the wall, overlapping at the corners on a layer of adobe mortar.

Following each individual brick should be a layer of adobe mortar, recommended to be at least an inch thick to make certain there is ample strength between the brick ’ s edges and also to provide a relative moisture barrier during the seasons where the arid climate does produce rain.

The lower the layer the worse it is.

In general, external alpha radiation is not harmful since alpha particles are effectively shielded by a few centimeters of air, a piece of paper, or the thin layer of dead skin cells.

The thick inner layer of the shell is composed of nacre or mother-of-pearl, which in many species is highly iridescent, giving rise to a range of strong and changeable colors, which make the shells attractive to humans as decorative objects, and as a source of colorful mother-of-pearl.

Often, the fact that sometimes only a thin surface layer of violet color is present in the stone or that the color is not homogeneous makes for a difficult cutting.

Much of the ACC transport is carried in this front, which is defined as the latitude at which a subsurface salinity minimum or a thick layer of unstratified Subantarctic Mode Water first appears, allowed by temperature dominating density stratification.

AEP ( AppleTalk Echo Protocol ) is a transport layer protocol designed to test the reachability of network nodes.

: The outermost layer, the zona glomerulosa is the main site for production of mineralocorticoids, mainly aldosterone, which is largely responsible for the long-term regulation of blood pressure.

It can be a raw bitstream, but it is usually a container format or an audio data format with defined storage layer.

In a semiconductor diode, the anode is the P-doped layer which initially supplies holes to the junction.

In such models, the behavior of the adhesive layer itself is neglected and only the adherents are considered.

Specifically, at speeds of OC-3 and above, the cost of segmentation and reassembly ( SAR ) hardware makes ATM less competitive for IP than Packet Over SONET ( POS ); because of its fixed 48-byte cell payload, ATM is not suitable as a data link layer directly underlying IP ( without the need for SAR at the data link level ) since the OSI layer on which IP operates must provide a maximum transmission unit ( MTU ) of at least 576 bytes.

The base and crown of these are composed of dentine separated by an uncalcified layer and they are replaced at intervals.

The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces.

Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization.

This type of cell wall is composed entirely of a thick layer of polysaccharides, which may be sulfated in the case of Halococcus.

In HPLC the sample is forced by a liquid at high pressure ( the mobile phase ) through a column that is packed with a stationary phase composed of irregularly or spherically shaped particles, a porous monolithic layer, or a porous membrane.

A typical forest is composed of the overstory ( canopy or upper tree layer ) and the understory.

The thyroid gland is covered by a thin fibrous sheath, the capsula glandulae thyroidea, composed of an internal and external layer.

The pattern now show a hypocellular superficial layer, followed by a middle layer composed predominantly of elastin fiber, and a deeper layer composed predominantly of collagen fibers.

The luminal surface of this squamous epithelium is covered by a layer of mucus ( mucociliary blanket ) which is composed of two layers: a mucinous layer and serous layer.

The superficial layer LPs ( SLLPs ), also known as Reinke ’ s space, is composed of amorphous substance and microfibrils which allows this cover layer to “ slide ” over the deep layer easily.

The outermost layer is known as the tunica externa formerly known as " tunica adventitia " and is composed of connective tissue.

The middle layer is called the myocardium and is composed of cardiac muscle which contracts.

The outermost layer of the Earth or the Earth's crust is composed of seven primary plates.

It is composed of a layer of mesothelium supported by a thin layer of connective tissue.

Keratin filaments are abundant in keratinocytes in the cornified layer of the epidermis ; these are cells which have undergone keratinization.

When ultraviolet rays penetrate the skin and damage DNA, thymidine dinucleotide ( pTpT ) fragments from damaged DNA will trigger melanogenesis and cause the melanocyte to produce melanosomes, which are then transferred by dendrite to the top layer of keratinocytes.

Biologically, calluses are formed by the accumulation of terminally differentiated keratinocytes in the outermost layer of skin.

Those keratinocytes found in the basal layer ( Stratum germinativum ) of the skin are sometimes referred to as " basal cells " or " basal keratinocytes ".

The fully cornified keratinocytes that form the outermost layer are constantly shed off and replaced by new cells.

It is thought that E2 serves as a negative regulator of expression for the oncogenes E6 and E7 in latently HPV-infected basal layer keratinocytes.

During cornification, the process whereby living keratinocytes are transformed into non-living corneocytes, the cell membrane is replaced by a layer of ceramides which become covalently linked to an envelope of structural proteins ( the cornified envelope ).

It is found largely in the upper spinous layer of epidermal keratinocytes and mutations in the gene encoding this protein have been associated with ichthyosis bullosa of Siemens.