Marker

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marker

[′märk·ər]
(immunology)
Any antigen that serves to distinguish cell types.
(ordnance)
A sign or signal for marking a location on land or water; frequently contains pyrotechnics.

Marker

 

a device for guiding a sower or planter to form interrows of a planned width. A marker consists of an extendable bar connected by a hinge to a sower or hitch. On the outer end of the bar is a disk, which is mounted at an angle and rotates freely; as it moves over the field, it leaves a furrow in the un-seeded area. On the next pass of the unit the furrow is used to guide the right front wheel or the inside edge of the right track of a tractor. Sowers and planters usually operate with right and left markers. The overlap (M) of the marker is determined according to the following formulas:

where a is the distance between the front wheels or the inside edges of the tracks, B is the distance between the extreme colters of the sower, and C is the size of the interrow.


Marker

 

an attachment to a single- or double-row sower that ensures parallel rows of seeds in subsequent passes. A marker consists of a beam with a weight on the end; the beam is secured to the front of the tractor. The tractor is steered so that the weight of the marker is above the track left by the planter wheel or marker disk on the preceding pass. Markers are often made reversible so that they can be used on both sides of the tractor.

marker

A sign, plaque, or monument that designates a building, site of historic importance, or boundary.

marker

markerclick for a larger image
Distance to go markers on the sides of runway.
An object displayed above ground level in order to indicate an obstacle or delineate a boundary (ICAO). Markers should be frangible, and those located near a runway or taxiway should be sufficiently low to ensure clearance for propellers and the engine pods of jet aircraft. The various types of markers are the distance-to-go markers, unpaved runway-edge markers, stop-way-edge markers, taxiway-edge markers, taxiway centerline markers, boundary markers, and unpaved taxiway-edge markers.
References in periodicals archive ?
To find out whether Total Lymphocyte Count, Body Mass Index, Haemoglobin and Albumin levels as low cost surrogate markers in predicting disease progression in HIV/AIDS.
Changes in these surrogate markers are usually the study endpoints, and endpoints are the measurements by which a drug's efficacy is judged.
Information on medications, complications related to polyneuropathy, and answers to survey questions about disabling symptoms were extracted for cases and controls as surrogate markers to quantify functional disability.
All of this is based on one surrogate marker imaging trial in a
patients experienced prolonged life and delayed disease progression) and this increased comfort levels about using CD4 T cell count as a surrogate marker for approval of future anti-HIV drugs.
MORE investigators selected a number of surrogate markers for increased lifetime exposure to estrogen in the osteoporotic study population and then sought to determine whether raloxifene's cancer-preventing effects were greater in those patients with the most lifetime estrogen exposure.
Without an accepted surrogate marker of some sort, immune treatments have been required to show that they can reduce clinical endpoints.
This report also indicates that almost half of respondents were unable to rate carotid intima-media thickness (CIMT) as being particularly good or bad as a surrogate marker for clinical end points.
While the primary objective of this study was to obtain safety and tolerance data for CPP-115 administered over 14 days, brain GABA levels were measured as a surrogate marker of potential efficacy, since CPP-115 is a second generation GABA aminotransferase inhibitor.
We used ferritin as a surrogate marker for iron overload, and we know that iron overload is an adverse prognostic factor in patients undergoing allogeneic stem-cell transplantation for thalassemia and also for patients with acute leukemia and myelodysplastic syndromes," he said in an interview.
Low glutathione level appears to be a strong predictor of risk of death in persons with HIV [2] -- but it is not yet known if glutathione level could be a surrogate marker for drug development.
In one study, investigators used Doppler ultrasound to measure common carotid artery intimal-medial wall thickness, a surrogate marker of atherosclerosis, in 80 subjects (Am.