Sickle cell trait describes a condition in which a person has one abnormal allele of the hemoglobin beta gene (is heterozygous), but does not display the severe symptoms of sickle cell disease that occur in a person who has two copies of that allele (is homozygous). Those who are heterozygous for the sickle cell allele produce both normal and abnormal hemoglobin (the two alleles are codominant with respect to the actual concentration of hemoglobin in the circulating cells). Sickle cell disease is a blood disorder wherein there is a single amino acid substitution in the hemoglobin protein of the red blood cells, which causes these cells to assume a sickle shape, especially when under low oxygen tension. Sickling and sickle cell disease also confer some resistance to malaria parasitization of red blood cells, so that individuals with sickle-cell trait (heterozygotes) have a selective advantage in environments where malaria is present. Symptoms and signs
Sickle cell trait is a hemoglobin genotype AS and is generally regarded as a benign condition. However, individuals with sickle cell trait may have rare complications. For example, in November 2010, Dr. Jeffery K. Taubenberger of the National Institutes of Health discovered the earliest proof of sickle-cell disease while looking for the virus of the 1918 flu during the autopsy of an African-American soldier. Taubenbergers autopsy results showed that the soldier had had a sickle-cell crisis that contributed to his death even though he had only one copy of the gene.
Roughness may refer to:

Surface roughness, the roughness of a surface
Roughness length, roughness as applied in meteorology
International Roughness Index, the roughness of a road
Hydraulic roughness, the roughness of land and waterway features
Roughness (psychophysics) in psychoacoustics refers to the level of dissonance
The roughness of a line or surface, measured numerically by the Hausdorff dimension
Roughness/resel, the resel/roughness of an image/volume
Unnecessary roughness, a type of foul in gridiron football

See also
Surface finish