Glossary 2009 Edition National Agricultural Library Agricultural Research Service, United States Department of Agriculture 10301 Baltimore Avenue Beltsville, MD 20705 USA http://www.nal.usda.gov Published in cooperation with: Inter-American Institute for Cooperation on Agriculture http://www.iica.int NAL Thesaurus Staff: Lori J. Finch, Thesaurus Coordinator Ruey-Shan Chen Nancy Z. Matthews Lynn Stanko 2 Symbols and Numbers 4-H Youth Development Program Definition The 4-H Youth Development Program is an international youth outreach organization founded in 1902 to foster agricultural, homemaking, leadership and other skills in young people. The 4-H name represents the ideals of the program with its focus on Head, Heart, Hands and Health. The program is administered by the United States Department of Agriculture Cooperative Extension Service. Definition Source NAL Thesaurus Staff Spanish Programa de Desarrollo Juvenil 4-H 3 A abdominal fat Definition Body fat located in the abdominal region. Definition Source NAL Thesaurus Staff Spanish grasa abdominal abnormal development Definition May be used for abnormal development in any organism, which is characterized by the change in the morphology of anatomical structures. Definition Source NAL Thesaurus Staff Spanish desarrollo anormal abortifacients Definition Chemical substances that interrupt pregnancy after implantation. Definition Source MeSH (Medical Subject Headings) Spanish abortifacientes abortion (plants) Definition premature termination of the development of pollen, gametes, embryos, seeds, fruits, flowers, and etc. Definition Source NAL Thesaurus Staff Spanish aborto (plantas) abscess Definition Accumulation of purulent material in tissues, organs, or circumscribed spaces, usually associated with signs of infection. Definition Source MeSH (Medical Subject Headings) Spanish abceso absorbance Definition A measure of the amount of light absorbed by a solution. It is measured by a colorimeter or spectrophotometer. Absorbance values are used to plot the growth of bacteria in suspension cultures and to determine the concentration of molecules in 4 solution. Definition Source NAL Thesaurus Staff Spanish absorbancia absorbents Definition A substance that takes liquid in through the surface and holds it. Definition Source NAL Thesaurus Staff Spanish absorbentes absorption Definition The taking in or incorporation of a substance. Definition Source NAL Thesaurus Staff Spanish absorción Accipitridae Definition Family including eagles, hawks and kites. Definition Source NAL Thesaurus Staff Spanish Accipitridae accuracy Definition The extent to which a measurement approaches the true value of the measured quantity. Definition Source NAL Thesaurus Staff Spanish exactitud Acer freemanii Definition Interspecific hybrid between Acer rubrum x Acer saccharinum. Definition Source NAL Thesaurus Staff Spanish Acer freemanii acetaminophen Definition Analgesic antipyretic derivative of acetanilide. It has weak anti-inflammatory properties and is used as a common analgesic, but may cause liver, blood cell, and kidney damage. Definition Source MeSH (Medical Subject Headings) Spanish 5 acetaminofeno Achillea lewisii Definition Interspecific hybrid between Achillea clavennae x Achillea tomentosa. Definition Source NAL Thesaurus Staff Spanish Achillea lewisii acid soils Definition Soil with a pH less than 7.0. Definition Source NAL Thesaurus Staff Spanish suelos ácidos acid-base balance Definition The balance between acids and bases in the blood plasma. Normally it results in a slightly alkaline state with an excess of hydroxyl ions in comparison to hydrogen ions. The balance is achieved by the offset of the ingestion and production of acidic and basic material by the amount of acidic and basic material metabolized and excreted by the body. Definition Source MeSH (Medical Subject Headings) Spanish balance ácido-base acidification Definition To lower the pH of a substance or material to below 7.0 Definition Source NAL Thesaurus Staff Spanish acidulación acidosis Definition A pathologic condition resulting from accumulation of acid or depletion of the alkaline reserve (bicarbonate) content of the blood and body tissues, and characterized by an increase in hydrogen ion concentration (decrease in pH). Definition Source MeSH (Medical Subject Headings) Spanish acidosis acidulants Definition 6 An additive added to a product to increase the acidity of the product. Acidulants are often added to food products to increase tartness. Definition Source NAL Thesaurus Staff Spanish acidulantes acinar cells Definition Any secreting cells lining an acinus of a compound gland. Definition Source NAL Thesaurus Staff Spanish células acinosas Aconitum cammarum Definition Probable interspecific hybrid between Aconitum variegatum x Aconitum napellus. Definition Source GRIN (Germplasm Resources Information Network) Spanish Aconitum cammarum acquired immunodeficiency syndrome Definition An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus ( HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993. Definition Source MeSH (Medical Subject Headings) Spanish síndrome de inmunodeficiencia adquirida actin Definition Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with myosin, actin is responsible for the contraction and relaxation of muscle. Definition Source MeSH (Medical Subject Headings) Spanish actina 7 Actinobacillus equuli Definition A species of bacteria that infects horses and pigs. Definition Source NAL Thesaurus Staff Spanish Actinobacillus equuli Actinobacillus lignieresii Definition A species of bacteria that infects cattle and sheep. Definition Source NAL Thesaurus Staff Spanish Actinobacillus lignieresii action potentials Definition The electric response of a nerve or muscle to its stimulation. Definition Source MeSH (Medical Subject Headings) Spanish potenciales de acción acute course Definition Short and relatively severe progression of disease. Definition Source MeSH (Medical Subject Headings) Spanish curso agudo acute phase proteins Definition Proteins that are secreted into the blood in increased or decreased quantities by hepatocytes in response to trauma, inflammation, or disease. These proteins can serve as inhibitors or mediators of the inflammatory processes. Certain acute-phase proteins have been used to diagnose and follow the course of diseases or as tumor markers. Definition Source MeSH (Medical Subject Headings) Spanish proteínas de fase aguda acute toxic class method Definition An alternative to the LD-50 test which uses fewer animals and classifies chemicals as very toxic, toxic, harmful or unclassified. Definition Source NAL Thesaurus Staff 8 Spanish método de clase tóxica aguda acute toxicity Definition Immediate or short-term adverse reaction of an organism to a single exposure to a chemical substance. Definition Source NAL Thesaurus Staff Spanish toxicidad aguda ad valorem duty Definition Tariff defined as a percentage of the value of an imported commodity or product. Definition Source NAL Thesaurus Staff Spanish derecho ad valorem adaptive radiation Definition Rapid divergent evolution of a more generalized ancestral species into a variety of more specialized species or subspecies which fill unoccupied ecological niches. Definition Source NAL Thesaurus Staff Spanish radiación adaptativa additive gene effects Definition Gene action which is the result of genes acting independently of genetic background so that each gene has an equal ability to be expressed and makes an independent contribution to the expression of the trait. Definition Source NAL Thesaurus Staff Spanish efectos genéticos aditivos Adequate Intakes Definition When sufficient scientific evidence is not available to estimate an average requirement, Adequate Intakes are set. Definition Source NAL Thesaurus Staff Spanish Ingestas Adecuadas adhesins Definition Cell-surface components or appendages of bacteria 9 that facilitate adhesion to other cells or to inanimate surfaces. Most fimbriae of gram-negative bacteria function as adhesins, but in many cases it is a minor subunit protein at the tip of the fimbriae that is the actual adhesin. In gram-positive bacteria, a protein or polysaccharide surface layer serves as the specific adhesin. Definition Source MeSH (Medical Subject Headings) Spanish adhesinas adhesives Definition A substance capable of holding materials together by surface attachment. It is a general term and includes cements, mucilage, and paste, as well as glue. Definition Source Wood Handbook, Glossary. Forest Products Laboratory. Spanish adhesivos adipokinetic hormone Definition Peptide hormones produced by some insect species stimulating the release of acylglycerols from the fat body which are used as an energy source by the flight muscles. There are several types of peptides with adipokinetic activity. These peptides are composed of 8-10 amino acids. Definition Source NAL Thesaurus Staff Spanish hormona adipocinética Adirondacks Definition