| PDL | pancreatic duct ligation; periodontal ligament; poorly differentiated lymphocyte; population doublin... |
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| PDT | photodynamic therapy; population doubling time |
| Pop | popliteal; population |
| POPLINE | Population Information Online |
| PP | diphosphate group; emphysema [pink puffers]; near point of accommodation [Lat. punctum proximum]; pa... |
| cross-sectional study | <epidemiology> A study in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with longitudinal studies which are followed over a period of time. Synonym: horizontal study. (18 Jul 2002) |
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| preclinical study | A study to test a drug, procedure or other medical treatment in animals. The aim is to collect data in support of safety. Preclinical studies are required before clinical trials can be started. (12 Dec 1998) |
| prospective study | <epidemiology> A study in which people are initially enrolled and then followed up at subsequent times. (05 Dec 1998) |
| study | 1. To apply the mind to; to read and examine for the purpose of learning and understanding; as, to study law or theology; to study languages. 2. To consider attentively; to examine closely; as, to study the work of nature. "Study thyself; what rank or what degree The wise Creator has ordained for thee." (Dryden) 3. To form or arrange by previous thought; to con over, as in committing to memory; as, to study a speech. 4. To make an object of study; to aim at sedulously; to devote one's thoughts to; as, to study the welfare of others; to study variety in composition. "For their heart studieth destruction." (Prov. Xxiv. 2) Origin: OE. Studie, L. Studium, akin to studere to study; possibly akin to Gr. Haste, zeal, to hasten; cf. OF. Estudie, estude, F. Etude. Cf. Etude, Student, Studio, Study, v. I. 1. A setting of the mind or thoughts upon a subject; hence, application of mind to books, arts, or science, or to any subject, for the purpose of acquiring knowledge. "Hammond . . . Spent thirteen hours of the day in study." (Bp. Fell) "Study gives strength to the mind; conversation, grace." (Sir W. Temple) 2. Mental occupation; absorbed or thoughtful attention; meditation; contemplation. "Just men they seemed, and all their study bent To worship God aright, and know his works." (Milton) 3. Any particular branch of learning that is studied; any object of attentive consideration. "The Holy Scriptures, especially the new Testament, are her daily study." (Law) "The proper study of mankind is man." (Pope) 4. A building or apartment devoted to study or to literary work. "His cheery little study." 5. A representation or rendering of any object or scene intended, not for exhibition as an original work of art, but for the information, instruction, or assistance of the maker; as, a study of heads or of hands for a figure picture. 6. A piece for special practice. See Etude. Source: Websters Dictionary (01 Mar 1998) |
| study, crossover | A type of clinical trial in which the study subjects receive each treatment in a random order. In this type of study, every patient serves as his or her own control. (12 Dec 1998) |
| study, cross-sectional | A study done at one time, not over the course of time. A cross-sectional study a disease such as aids might be designed to learn its prevalence and distribution within the population at one point in time. Also known as a synchronic study. (12 Dec 1998) |
| study, diachronic | See: Study, longitudinal. (12 Dec 1998) |
| study, longitudinal | A study done over the passage of time. For example, a longitudinal study of children with down syndrome (trisomy 21) might involve the study of 100 children with this condition from birth to 10 years of age. Also called a diachronic study. The opposite of a cross-sectional (synchronic) study. (12 Dec 1998) |
| study, preclinical | A study to test a drug, procedure or medical treatment in animals. The aim is to collect data in support of safety. Preclinical studies are required before clinical trials can be started. (12 Dec 1998) |
| study, synchronic | See: Study, cross-sectional. (12 Dec 1998) |
| synchronic study | <epidemiology> A study in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with longitudinal studies which are followed over a period of time. Synonym: horizontal study. (18 Jul 2002) |
| diachronic study | A study done over the course of time. For example, a longitudinal study of children with Down syndrome (trisomy 21) might involve the study of 100 children with this condition from birth to 10 years of age. Also called a longitudinal study. The opposite of a synchronic (cross-sectional) study. (12 Dec 1998) |
| double-blind study | A study in which neither the experimenter nor any other assessor of the results, including patients, know which group is subject to which procedure, thus helping assure that the biases or expectations of either will not influence the results. (05 Mar 2000) |
| epidemiologic study characteristics | Types and formulations of studies used in epidemiological and clinical research. (12 Dec 1998) |
| twin study | A method of detecting genetic causes in human traits and genetic factors in behaviour using sets of twins. (12 Dec 1998) |