Helix Midnight | Medium Feel Mattress with Pressure Relief & Helix Sleep

A helix (; pl. helices) is a shape like a cylindrical coil spring or the thread of a machine screw. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved". A "filled-in" helix – for example, a "spiral" (helical) ramp – is a surface called a helicoid.

A mattress is a large, usually rectangular pad for supporting a person lying down, especially for sleeping. It is designed to be used as a bed, or on a bed frame as part of a bed. Mattresses may consist of a quilted or similarly fastened case, usually of heavy cloth, containing materials such as hair, straw, cotton, foam rubber, or a framework of metal springs. Mattresses may also be filled with air or water.

Mattresses are usually placed on top of a bed base which may be solid, as in the case of a platform bed, or elastic, such as an upholstered wood and wire box spring or a slatted foundation. Popular in Europe, a divan incorporates both mattress and foundation in a single upholstered, footed unit. Divans have at least one innerspring layer as well as cushioning materials. They may be supplied with a secondary mattress or a removable "topper". Mattresses may also be filled with air or water, or a variety of natural fibers, such as in futons. Kapok is a common mattress material in Southeast Asia, and coir in South Asia.

Midnight is the transition time from one day to the next – the moment when the date changes, on the local official clock time for any particular jurisdiction. By clock time, midnight is the opposite of noon, differing from it by 12 hours.

Solar midnight is the time opposite to solar noon, when the Sun is closest to the nadir, and the night is equidistant from sunset and sunrise. Due to the advent of time zones, which regularize time across a range of meridians, and daylight saving time, solar midnight rarely coincides with 12 midnight on the clock. Solar midnight depends on longitude and time of the year rather than on time zone. In ancient Roman timekeeping, midnight was halfway between dusk and dawn (i.e., solar midnight), varying according to the seasons.

In some Slavic languages, "midnight" has an additional geographic association with "north" (as "noon" does with "south"). Modern Polish, Belarusian, Ukrainian, and Serbian languages preserve this association with their words for "midnight" or "half-night" (północ, поўнач, північ, поноћ) also meaning "north".

Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.^: 445 Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure.

Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m²); similarly, the pound-force per square inch (psi, symbol lbf/in²) is the traditional unit of pressure in the imperial and US customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the unit atmosphere (atm) is equal to this pressure, and the torr is defined as 1⁄760 of this. Manometric units such as the centimetre of water, millimetre of mercury, and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.

Relief is a sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term relief is from the Latin verb relevare, to raise (lit. to lift back). To create a sculpture in relief is to give the impression that the sculpted material has been raised above the background plane. When a relief is carved into a flat surface of stone (relief sculpture) or wood (relief carving), the field is actually lowered, leaving the unsculpted areas seeming higher. The approach requires a lot of chiselling away of the background, which takes a long time. On the other hand, a relief saves forming the rear of a subject, and is less fragile and more securely fixed than a sculpture in the round, especially one of a standing figure where the ankles are a potential weak point, particularly in stone. In other materials such as metal, clay, plaster stucco, ceramics or papier-mâché the form can be simply added to or raised up from the background. Monumental bronze reliefs are made by casting.

There are different degrees of relief depending on the degree of projection of the sculpted form from the field, for which the Italian and French terms are still sometimes used in English. The full range includes high relief (Italian alto-rilievo, French haut-relief), where more than 50% of the depth is shown and there may be undercut areas, mid-relief (Italian mezzo-rilievo), low relief (Italian basso-rilievo, French: bas-relief), and shallow-relief (Italian rilievo schiacciato), where the plane is only very slightly lower than the sculpted elements. There is also sunk relief, which was mainly restricted to Ancient Egypt (see below). However, the distinction between high relief and low relief is the clearest and most important, and these two are generally the only terms used to discuss most work.

The definition of these terms is somewhat variable, and many works combine areas in more than one of them, rarely sliding between them in a single figure; accordingly some writers prefer to avoid all distinctions. The opposite of relief sculpture is counter-relief, intaglio, or cavo-rilievo, where the form is cut into the field or background rather than rising from it; this is very rare in monumental sculpture. Hyphens may or may not be used in all these terms, though they are rarely seen in "sunk relief" and are usual in "bas-relief" and "counter-relief". Works in the technique are described as "in relief", and, especially in monumental sculpture, the work itself is "a relief".

Reliefs are common throughout the world on the walls of buildings and a variety of smaller settings, and a sequence of several panels or sections of relief may represent an extended narrative. Relief is more suitable for depicting complicated subjects with many figures and very active poses, such as battles, than free-standing "sculpture in the round". Most ancient architectural reliefs were originally painted, which helped to define forms in low relief. The subject of reliefs is for convenient reference assumed in this article to be usually figures, but sculpture in relief often depicts decorative geometrical or foliage patterns, as in the arabesques of Islamic art, and may be of any subject.

Rock reliefs are those carved into solid rock in the open air (if inside caves, whether natural or human-made, they are more likely to be called "rock-cut"). This type is found in many cultures, in particular those of the Ancient Near East and Buddhist countries. A stele is a single standing stone; many of these carry reliefs.

Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.

Sleep occurs in repeating periods, during which the body alternates between two distinct modes: rapid eye movement sleep (REM) and non-REM sleep. Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual paralysis of the body. Dreams are a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep.

During sleep, most of the body's systems are in an anabolic state, helping to restore the immune, nervous, skeletal, and muscular systems; these are vital processes that maintain mood, memory, and cognitive function, and play a large role in the function of the endocrine and immune systems. The internal circadian clock promotes sleep daily at night, when it is dark. The diverse purposes and mechanisms of sleep are the subject of substantial ongoing research. Sleep is a highly conserved behavior across animal evolution, likely going back hundreds of millions of years, and originating as a means for the brain to cleanse itself of waste products. In a major breakthrough, researchers have found that cleansing, including the removal of amyloid, may be a core purpose of sleep.

Humans may suffer from various sleep disorders, including dyssomnias, such as insomnia, hypersomnia, narcolepsy, and sleep apnea; parasomnias, such as sleepwalking and rapid eye movement sleep behavior disorder; bruxism; and circadian rhythm sleep disorders. The use of artificial light has substantially altered humanity's sleep patterns. Common sources of artificial light include outdoor lighting and the screens of electronic devices such as smartphones and televisions, which emit large amounts of blue light, a form of light typically associated with daytime. This disrupts the release of the hormone melatonin needed to regulate the sleep cycle.

With or WITH may refer to:

• With, a preposition in English
• Carl Johannes With (1877–1923), Danish doctor and arachnologist
• With (character), a character in D. N. Angel
• With (novel), a novel by Donald Harrington
• With (album), a 2014 album by TVXQ
• With (EP), a 2021 EP by Nam Woo-hyun