Manzanita is a common name for many species of the genus Arctostaphylos. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from Southern British Columbia and Washington to Oregon, Arizona, New Mexico and Texas in the United States, throughout Mexico. Manzanitas can live in places with little water, they are characterized by smooth orange or red bark and twisting branches. There are 105 species and subspecies of manzanita, 95 of which are found in the Mediterranean climate and colder mountainous regions of California, ranging from ground-hugging coastal and mountain species to small trees up to 20 feet tall. Manzanitas carry berries in spring and summer; the berries and flowers of most species are edible. The word manzanita is the Spanish diminutive of manzana. A literal translation would be little apple; the name manzanita is sometimes used to refer to species in the related genus Arbutus, known by that name in the Canadian area of the tree's range, but is more known as madroño, or madrone in the United States.

Native Americans in Northern California made a tisane from manzanita leaves to treat poison oak rash. The leaves contain chemicals with a mildly disinfectant quality, can be used for mild urinary tract infections; the berries are a good food, as they can be stored. Once stored and dried, the berries can be ground into a coarse meal; the berries can be eaten ripe or green for a sour taste. They are good used as a thickener or sweetener in other dishes. Native Americans used the leaves as toothbrushes. Manzanitas are useful as ornamental plants in gardens in the western United States and similar climate zones, they are evergreen drought-tolerant, have picturesque bark and attractive flowers and berries, come in many sizes and growth patterns. Arctostaphylos columbiana, for example, is hardy enough to be used for highway landscaping in western Oregon and Washington. Arctostaphylos'Emerald Carpet', A. uva-ursi, other low-growing manzanitas are valuable evergreen groundcovers for dry slopes. Larger varieties, such as Arctostaphylos.'Dr.

Hurd,' can be grown as individual specimens, pruned to emphasize the striking pattern and colors of the branches. They prefer light, well-drained soil, although the low-growing ground covers will tolerate heavier soils. Manzanita branches are popular as decoration, due to their unique shape and strength when dried. Florists sometimes use them as centerpieces at wedding receptions and other events adding hanging votive candles, beaded gems and small flowers to them; the wood is notoriously hard to cure due to cracking against the grain, giving it few uses as lumber. The slow growth rate and many branchings further decrease the sizes available; some furniture and art employ whole round branches, which reduces cracking and preserves the deep red color. The dead wood decays and can last for many years, on and off the plant. Sunlight smooths and bleaches manzanita to light grey or white, rendering it superficially akin to animal bones; because of this and the stunted growth of many species, manzanita is collected in its more unusual shapes, giving it the nickname mountain driftwood.

Manzanita wood is used as perches for parrots and other large pet birds. The branches of the larger species are long-lasting for this purpose; some aquarium keepers use sandblasted manzanita as driftwood in planted aquaria because of its attractive forked growth and its chemical neutrality. If properly cleaned and cured, it holds up well over extended periods of submersion; the wood is resistant to the leaching of tannins into the water column, a problem found with other aquarium driftwoods. When used as driftwood, manzanita must be either weighted down for several weeks or soaked first to counteract the wood's natural buoyancy when it has been dried and cured; the green wood does not float. Manzanita wood, when dry, is excellent for burning in a campfire, fireplace, or stove, it burns at a high temperature for long periods. However, caution should be exercised, because the high temperatures can damage thin-walled barbecues, crack cast iron stoves or cause chimney fires. During World War II, Manzanita root burls were used as an expedient native material to make smoking pipes due to its relation and similar fire-resistant properties to then-unavailable imported briar.

Labeled as "Mission Briar", it was harvested for the remainder of the war, stopping soon after when supplies of imported briar once again became available. Some manzanita species are among the rarest plants in the world. Arctostaphylos hookeri ravenii, an endemic species, is the most endangered and restricted plant in the mainland United States. In 1987 only one specimen remained, at a secret location in the Presidio of San Francisco National Historic Landmark District in San Francisco, California; this plant has since been cloned. Arctostaphylos franciscana, a species native to San Francisco, had not been seen growing wild since 1947 until it was spotted growing in the Presidio of San Francisco in October 2009. Caltrans transplanted this specimen on 23 January 2010 to make way for the Doyle Drive Replacement Project. Transplanting costs were funded in part by Federal Highways Administration, The Presidio of San Francisco, private donors. "Arctostaphylos hookeri, subspecies franciscana", a scrubby, thin-twigged bush, riddled with the webs of miniature spiders, resides in a corner of the California section of The Str

Length time bias is an overestimation of survival duration due to the relative excess of cases detected that are asymptomatically progressing, while fast progressing cases are detected after giving symptoms. It is a form of selection bias, a statistical distortion of results that can lead to incorrect conclusions about factual data. While the raw data of a study may itself be objective and independent, statistical analysis requires parametric inputs of frequency and length of time, some arbitrary choice of design originating in the statistician and not the data. If points are chosen randomly in an attempt to prevent observer selection bias, this choice of method itself amounts to a grand bias, because longer or more complex intervals increase possibilities for false detection of significance. Length time bias is discussed in the context of the benefits of cancer screening, it can lead to the perception that screening leads to better outcomes when in reality it has no effect. Fast-growing tumors have a shorter asymptomatic phase than slower-growing tumors.

Thus, there is a shorter period of time during which the cancer is present in the body but not yet large enough to cause symptoms, that would cause the patient to seek medical care and be diagnosed without screening. As a result, if the same number of slow-growing and fast-growing tumors appear in a year, the screening test detects more slow-growers than fast-growers. If the slow growing tumors are less to be fatal than the fast growers, the people whose cancer is detected by screening do better, on average, than the people whose tumors are detected from symptoms if there is no real benefit to catching the cancer earlier; that can give the impression that detecting cancers by screening causes cancers to be less dangerous if less dangerous cancers are more to be detected by screening. Reference worksPorta, Miquel, ed.. "Length Bias". A Dictionary of Epidemiology. Oxford University Press. ISBN 9780199976720

S2, SB1, SM2 are disability swimming classifications used for categorizing swimmers based on their level of disability. People in this class have limited use of their arms, no or limited use of their hands and trunk. Swimmers in this class have a variety of different disabilities including cerebral palsy and amputations. Swimmers in this class have a number of events they can participate in including the 50m and 100m Freestyle, 200m Freestyle, 50m Backstroke, 50m Butterfly, 50m Breaststroke and 150m Individual Medley events; this classification is for swimming. In the classification title, S represents Freestyle and Butterfly strokes. SB means breaststroke. SM means individual medley. Swimming classifications are on a gradient, with one being the most physically impaired to ten having the least amount of physical disability. Jane Buckley, writing for the Sporting Wheelies, describes the swimmers in this classification as being: "able to use their arms with no use of their hands, legs or trunk Or have severe coordination problems in four limbs.

Similar disabilities to Class 1 but these athletes would have more propulsion by use of their arms or legs." This class includes people with several disability types include cerebral palsy, short stature and amputations. ISOD amputee A9 swimmers may be found in several classes; these include S2, S3, S4, S5 and S8. Prior to the 1990s, the A9 class was grouped with other amputee classes in swimming competitions, including the Paralympic Games. Swimmers in this class have a similar stroke stroke rate to able bodied swimmers; the nature of a person's amputations in this class can effect their physiology and sports performance. Because of the potential for balance issues related to having an amputation, during weight training, amputees are encouraged to use a spotter when lifting more than 15 pounds. Lower limb amputations effect a person's energy cost for being mobile. To keep their oxygen consumption rate similar to people without lower limb amputations, they need to walk slower; because they are missing a limb, amputees are more prone to overuse injuries in their remaining limbs.

Common problems with intact upper limbs for people in this class include rotator cuffs tearing, shoulder impingement and peripheral nerve entrapment. One of the disability groups in this classification is swimmers with cerebral palsy, including CP1 and CP2 classified swimmers; some CP1 swimmers in this class require floaters to race. The use of such devices is not allowed in IPC sanctioned events, but is allowed in CP-ISRA sanctioned ones. CP1 swimmers tend to have a passive normalized drag in the range of 1.3 to 1.7. This puts them into the passive drag band of PDB1, PDB3. CP1 sportspeople tend to use electric wheelchairs, they may have controlled twitches. They have limited of their trunk and limbs; when participating in sport, CP1 competitors tend to have low energy expenditure. This bodily activity can spike their metabolic rate. CP2 swimmers tend to have a passive normalized drag in the range of 1.0 to 1.1. This puts them into the passive drag band of PDB4. CP2 swimmers tend to use electric wheelchairs.

They may have controlled twitches. This bodily activity can spike their metabolic rate, they can operate a manual wheelchair but this is restricted because of motor control issues. Functional control issues most of their limbs; when participating in sport, CP2 competitors tend to have low energy expenditure. CP2 competitors have better upper body control when compared to CP1. SS2 swimmers may be found S1 and S5. Men in this class are 130 centimetres tall or less, with an arm length equal to or less than 59 centimetres; when their standing height and arm length are added together, the distance is equal to or less than 180 centimetres. For women in this class, the same measurements are 125 centimetres, 57 centimetres and 173 centimetres. There are two types of syndromes that cause short stature. One is disproportionate limb size on a normal size torso; the second is proportionate, where they are small for their average age. There are a variety of causes including skeletal dysplasia and growth hormone deficiencies.

Short stature can cause a number of other disabilities including eye problems, joint defects, joint dislocation or limited range of movement. People with spinal cord injuries compete in this class, including F2 sportspeople; this is wheelchair sport classification that corresponds to the neurological level C6. In the past, this class was known as 1A Complete. Disabled Sports USA defined the anatomical definition of this class in 2003 as, "Have functional elbow flexors and wrist dorsi-flexors. May have elbow extensors but do not have wrist palmar flexors. May have shoulder weakness. Have no sitting balance." People with C4 lesions have head control, limited respiratory endurance. People with C5 lesions have abduction of the arms, flexion of the arm. People with C6 lesions have abduction and flexion of the arms, wrist extension; the location of lesions on different vertebrae tend to be associated with disability levels and functionality issues. People with C4 lesions can control electronic devices using a mouth controlled joystick.

People with a lesion at C5 or C6 have an impairment that effects the use of their hands and lower arm. People with C5 can perform some actions with one of their arms, can propel a wheelchair with modified rims that make it easier to do. People with C6 can have a weak grasp with their wrist, they can roll over in bed. They have some independence in that they can groom themselves without assistance, they may be able to transfer themselves to a wheelchair