rad: a unit-absorbed dose of ionizing radiation equivalent to the absorption of 100 erg per gram of irradiated material.
Radiation hybrid: a hybrid cell containing small fragments of irradiated human chromosomes. Maps of irradiation sites on chromosomes for the human, rat, mouse, and other genomes provide important markers, allowing the construction of very precise STS maps indispensable to studying multifactorial diseases. See also -- sequence tagged site.
Random Assignment: a process (such as a coin toss) for sample selection that gives each individual in a given population an equal chance of being included (also known as random selection).
Random Error: it is the portion of variation in a measurement that has no apparent connection to any other measurement or variable, generally regarded as due to chance.
Randomization: the process of assigning trial subjects to treatment or control groups using an element of chance to determine the assignments in order to reduce bias. (from ICH E6).
Rapid (mini) HIA: a rapid or "mini" HIA, as the name suggests, is done quickly. It may be a "desk top" exercise, reliant on information which is already available already available "off the shelf" (Parry and Stevens, 2001), or through a half day or one day workshop with key stakeholders (Barnes et al., 2001). In either case, there is usually a minimum quantification of the potential health impacts which are identified.
Rare-Cutter Enzyme: see -- restriction-enzyme cutting site.
ras Gene: a family of genes that encode similar cell membrane-bound proteins involved in signal transduction. Three types, K-ras, N-ras, and H-ras, are the widely studied ras genes in human tumors. Their proto-oncogene becomes activated by point mutations, most often in specific codons, of the gene sequence.
Ratio of Male to Female AIDS Cases: the quotient between the number of new cases registered from Acquired Immunodeficiency Syndrome (AIDS) of male to female cases, in a specific year, for a given country, territory, or geographic area.
Rationing: restricting supply of services according to implicit or explicit criteria, where demand exceeds supply.
RB: the first tumor suppressor gene to be discovered. It is a 4.7-kilobase gene, located on chromosome 13q14, and encodes a 110,000-dalton nuclear phosphoprotein that suppresses the cell cycle. Absence of RB is the cause of retinoblastoma, and research is revealing that it is involved in the pathogenesis of many other neoplasms.
RCT: randomized controlled trial.
Real Gross Domestic Product (Real GDP): GDP which is expressed in purchasing power parity (PPP) and adjusted to the relative domestic purchasing power of the national currency as compared to the US dollar.
Reassuring Fetal Heart Rate Monitor Strip/Tracing: the absence of fetal heart rate patterns defined as nonreassuring (see Nonreassuring Fetal Heart Rate Monitor Strip/Tracing).
Receiver Operator Characteristics (ROC): these curves are the best way to demonstrate the relationships between sensitivity and specificity. These curves plot sensitivity (true positive rate) against the false positive rate (1-specificity). Along any particular ROC curve one can observe the impact of compromising the true positive and false positive rates. As the requirement that a test have a high true positive rate increases, the false positive rate will also increase.
Recessive Gene: a gene which will be expressed only if there are 2 identical copies or, for a male, if one copy is present on the X chromosome.
Reciprocal Translocation: when a pair of chromosomes exchange exactly the same length and area of DNA. Results in a shuffling of genes.
Recombinant: a gene that has been isolated and recombined with other sequences responsible for gene expression.
Recombinant Clone: clone containing recombinant DNA molecules. See also -- recombinant DNA technology.
Recombinant DNA: a new DNA sequence formed by the combination of two non-homologous DNA molecules.
Recombinant DNA Molecules: a combination of DNA molecules of different origin that are joined using recombinant DNA technologies.
Recombinant DNA Technology: procedure used to join together DNA segments in a cell-free system (an environment outside a cell or organism). Under appropriate conditions, a recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.
Recombination: the process by which progeny derive a combination of genes different from that of either parent. In higher organisms, this can occur by crossing over. See also -- crossing over, mutation.
Rectocele: bulging of the rectum into the space normally occupied by the vagina, suggesting weakness of the pelvic floor.
Rectum: last segment of colon, or large intestine, the lowest part of the bowel found right before the anus.
Recurrent Expenditure: 'Ongoing expenditure' such as salaries, wages, travelling expenses, drugs, etc.
Reference Price: the maximum price for a group of equal or similar products (mostly pharmaceuticals) the third party payer is ready to reimburse.
Reform: a purposeful, dynamic process that involves systematic policy, structural and process changes and is aimed at achieving desired goals.
Regeneration: regeneration is a broad concept used to describe a wide variety of measures that are designed to revive disadvantaged (mainly urban) areas. This might include -modifying the physical environment; -altering lifestyles; -improving leisure opportunities; -enhancing the training and employment prospects of local residents; -reducing stress, anxiety and fear; -strengthening control over people's lives and fostering empowerment; -improving access to public services; and -enhancing relationships between local residents and public sector agencies. Since the second world war there have been many regeneration initiatives -- the most recent being the neighborhood renewal and other related programs -- and many inner city areas have been "regenerated" more than once. ((Hirschfield et al., 2001).
Regressive Tax: a tax in which the poor pay a larger fraction of their income than the rich.
Regulation: intervention by government, by means of rules, in health care markets or systems.
Regulatory Capture: a deviance in transaction practice by which one of the parties with vested interests in the deal exerts pressure on the regulators in order to obtain better conditions in the deal.
Regulatory Region or Sequence: a DNA base sequence that controls gene expression.
Rehab Urinals: portable receptacles for collecting urine, usually made of plastic or metal, that is specifically designed to aid individuals who have decreased dexterity or functional ability.
Relative Biologic Effectiveness (RBE): a ratio of the absorbed dose of a reference radiation to the absorbed dose of a test radiation to produce the same level of biologic effect, other conditions being equal.
Relative Risk: the ratio of risk of disease or death among the exposed to that of the risk among the unexposed; this usage is synonymous with risk ratio. If the relative risk is higher than 1, there is a positive association between the exposure and the disease; if it is less than 1, there is negative association.
Reliability: a study situation in which different researchers conduct the same study using the same data collection instruments and obtain the same results. The degree of stability exhibited when a measurement is repeated under identical conditions. Reliability refers to the degree to which the results obtained by a measurement procedure can be replicated. Lack of reliability may arise from divergences between observers or instruments of measurement or instability of the attribute being measured.
rem: the old unit of dose equivalent. It is the product of the absorbed dose in rads and modifying factor and is being replaced by the sievert.
Remuneration: refers to the activity of compensating health professionals for their time and effort in providing care.
Replicability: a characteristic of study design that means a study can be repeated and produce a similar outcome.
Representative Sample: a sample that provides a close approximation of the population studied, making it possible to generalize back to the population from which it was drawn.
Repetitive DNA: sequences of varying lengths that occur in multiple copies in the genome; it represents much of the human genome.
Reporter Gene: see -- marker.
Reproductive Health: reproductive health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity, in all matters relating to the reproductive system and to its functions and processes. Reproductive health therefore implies that people are able to have a satisfying and safe sex life and that they have the capability to reproduce and the freedom to decide if, when and how often to do so. Implicit in this last condition are the right of men and women to be informed of and to have access to safe, effective, affordable and acceptable methods of family planning of their choice, as well as other methods of their choice for regulation of fertility which are not against the law, and the right of access to appropriate health-care services that will enable women to go safely through pregnancy and childbirth and provide couples with the best chance of having a healthy infant. In line with the above definition of reproductive health, reproductive health care is defined as the constellation of methods, techniques and services that contribute to reproductive health and well-being by preventing and solving reproductive health problems. It also includes sexual health, the purpose of which is the enhancement of life and personal relations, and not merely counseling and care related to reproduction and sexually transmitted diseases. (ICPD Program of Action, A/CONF.171/13, paragraph 7.2.)
Reproductive Health Care: the sum total of services (clinical treatment, counseling, information, and education) and referrals of services as required to address individuals' needs for health care related to human sexuality and reproduction, including: fertility regulation, prenatal care, safe birth, post-natal care, infertility, abortion, and reproductive tract infections (including sexually transmitted infections and diseases).
Reproductive Rights: reproductive right rest on the recognition of the basic right of all couples and individuals to decide freely and responsibly the number, spacing and timing of their children and to have the information and means to do so, and the right to attain the highest standard of sexual and reproductive health. They also include the right of all to make decisions concerning reproduction free of discrimination, coercion and violence.
Reproductive Tract Infection (RTI): any infection associated with the reproductive/sexual organs; RTIs may be the result of endogenous infections (such as bacterial vaginosis or candida), sexually transmitted infections/diseases (such as HIV/AIDS, trichomonas or gonorrhea), or infections caused by a procedural complication (such as that related to induced abortion or other gynecological surgery).
Research: any systematic inquiry that involves collecting data and disseminating the results.
Research (Study) Design: a formalized and usually systematic plan to collect data that will inform a hypothesis.
Researcher: any person who undertakes to conduct research (collect data).
Resident Assessment Protocol (RAP): part of the Minimum Data Set that assists the nurse to assess the cause of various disruptions or conditions. The RAP provides a systematic method of assessment and is used in the development of the care plan for the individual residing in a nursing home.
Residual Urine: retention of urine in the bladder after voiding due to incomplete emptying.
Resolution: degree of molecular detail on a physical map of DNA, ranging from low to high.
Resource Allocation: the process of deciding what is needed to carry out an activity and providing for those needs. This can include making provision for financial resources (money), capital resources (such as buildings and computer hardware) and staff resources (including the number of staff needed and the skill mix required).
Resources: the basic inputs to production -- the time and abilities of individuals (human resources), raw materials such as land and natural resources (air, water, minerals, etc.), transformation and accumulations of these into capital (facilities, equipment) and knowledge production processes (technologies).
Responsiveness: one of the three goals of the health system to meet people's legitimate non-health expectations about how the system treats them.
Responsible Registrant: an appropriate representative of the trial's primary Sponsor. The Responsible Registrant is responsible for ensuring that the trial is properly registered. The primary Sponsor may or may not be the primary funder. The responsible registrant should make every reasonable effort to ensure that a trial is registered once and only once in any one register, and that the trial is registered in the fewest number of registers necessary to meet applicable regulations.
Restraints: medications or devices (e.g., belts, straps, jackets, chair) used to immobilize a person.
Restriction Endonuclease: an enzyme that recognizes and cleaves a specific DNA sequence (usually 4-10 nucleotide bases long). Enzymes that cleave DNA at specific DNA sequences.
Restriction Enzyme, Endonuclease: a protein that recognizes specific, short nucleotide sequences and cuts DNA at those sites. Bacteria contain over 400 such enzymes that recognize and cut more than 100 different DNA sequences. See also -- restriction enzyme cutting site.
Restriction Enzyme Cutting Site: a specific nucleotide sequence of DNA at which a particular restriction enzyme cuts the DNA. Some sites occur frequently in DNA (e.g., every several hundred base pairs); others much less frequently (rare-cutter; e.g., every 10,000 base pairs).
Restriction Fragment Length Polymorphism (RFLP): a polymorphic difference in DNA sequence between individuals that can be recognized by restriction endonucleases. Variation between individuals in DNA fragment sizes cut by specific restriction enzymes; polymorphic sequences that result in RFLPs are used as markers on both physical maps and genetic linkage maps. RFLPs usually are caused by mutation at a cutting site. See also marker, polymorphism.
Retrospective Data: data that are collected by reviewing past records or asking subjects about their past experience(s).
Retrospective HIA: retrospective HIA is carried out after a program or project has been completed. It is used to inform the ongoing development of existing work.
Retrospective Payment: a payment scheme whose level is determined only after services have been provided.
Retroviral Infection: the presence of retroviral vectors, such as some viruses, which use their recombinant DNA to insert their genetic material into the chromosomes of the host's cells. The virus is then propagated by the host cell.
Reverse Transcriptase: an enzyme used by retroviruses to form a complementary DNA sequence (cDNA) from their RNA. The resulting DNA is then inserted into the chromosome of the host cell. An enzyme discovered in retro-viruses that has the unique ability to transcribe DNA from and RNA template. This is the reverse of the normal physiologic process.
Ribonucleotide: see -- nucleotide.
Ribose: the five-carbon sugar that serves as a component of RNA. See also -- ribonucleic acid, deoxyribose.
Ribosomal RNA (rRNA): a class of RNA found in the ribosomes of cells.
Ribosomes: small cellular components composed of specialized ribosomal RNA and protein; site of protein synthesis. See also -- RNA.
Risk: the chance of probability that an event will occur. The proportion of unaffected individuals who, on average, will contract the disease of interest over a specified period of time. Results of a trial are often expressed as absolute or relative risk reductions. The absolute difference is the actual difference between the units of the difference. In relative risk, the differences are the percentage change. Relative risk reductions often sound much more dramatic than do the absolute values. One must consider the prevalence of a disease when evaluating risk reductions. Where there is a low prevalence of a disease process, small risk reductions become unimpressive and must be evaluated in terms of the benefits of a particular mode of therapy.
Risk Aversion: the extent to which an individual is willing to pay to reduce variation in losses or income due to random events.
Risk Communication: in genetics, a process in which a genetic counselor or other medical professional interprets genetic test results and advises patients of the consequences for them and their offspring.
Risk Factor: quality that makes a person more susceptible to a specific disease.
Risk Pooling: the practice of bringing several risks together for insurance purposes in order to balance the consequences of the realization of each individual risk.
Risk Rating: technique for adjusting insurance premiums according to the relative risk insured.
Risk Selection: the practice of singling out or disaggregating a particular risk from a pool of insured risks.
RNA (Ribonucleic Acid): a chemical found in the nucleus and cytoplasm of cells; it plays an important role in protein synthesis and other chemical activities of the cell. The structure of RNA is similar to that of DNA. There are several classes of RNA molecules, including messenger RNA, transfer RNA, ribosomal RNA, and other small RNAs, each serving a different purpose.
Roentgen (R): an internationally accepted unit of radiation quantity; it is the quantity of "X-ray or gamma irradiation such that the associated corpuscular emission per 0.001293 g or air produces, in air, ions carrying 1 esu of quantity of electricity of either sign". X-rays originate outside the nucleus.
Runt Disease: a condition of dwarfing that follows the injection of mature allogeneic immunologically competent cells into immunologically immature recipients. It is characterized by failure to thrive, lymph node atrophy, hepatomegaly and splenomegaly, anemia, and diarrhea.
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