Devised originally by René F. Thom (1923-2002) to model mathematically Waddington’s epigenetic landscape. It is a theory of dynamical systems based on analogy with topographical form and dealing with instabilities in a limited sub-class of dynamical systems that can be described by potential functions. If a system consists of n variables, then one of its …
Author Archives: Brian Hopkins
Caregiver Interaction Scale (CIS)
An observationalmeasure for early childhood contexts. The measure is designed to capture theaffective valence of teacher-child interaction, with a particular focus on theextent to which teachers are positive, responsive, and engaged with children. Atrained observer visits a classroom and observes the lead and/or aide teacherinteracting as they normally would for approximately 1 hour. The observer …
Case-comparison design
A research design in which cases of a given disease or other condition are sampled for study. A comparison sample of persons not having the condition is also recruited, as far as possible from the same basic population. These samples are then compared on exposure to hypothesised risks for the condition. See Epidemiology, Odds ratio, …
Cardiac muscle
Involuntary striated muscle found only found in the wall of the heart, with other involuntary muscles being in general smooth. It has a longer refractory period than skeletal striated muscle elsewhere in the body, and a consequence does not fatigue. See Catecholamines, Creatine, Electrolyte, Smooth (or involuntary) muscle, Striated (or striped or voluntary) muscle
Cardiovascular accidents (CVAs)
A hemorrhage or thrombosis involving the arteries that supply the heart; a ‘heart attack’. Risk factors associated with CVAs include smoking, ‘bad’ cholesterol (LDL-cholesterol), but not ‘good’ cholesterol (HDL-cholesterol), and high blood pressure. See Cholesterol, Environmental tobacco smoke (ETS), Nicotine, Risk factors
Carcinogen
A substance or agent that causes cancer, and which are often (but not necessarily) mutagens or teratogens. They cause cancer by altering DNA. With the exception of tobacco, what is sometimes not recognised by the general public is that almost all carcinogens consumed by humans are contained in plants, something that prevents plants from being …
Carbohydrates
Any group of organic compounds consisting only of the union of carbon, hydrogen and oxygen atoms. This union results in a sugar molecule, the basic building block of every carbohydrate (with starches and fibers being essentially chains of sugar molecules). There are two classes of carbohydrates: complex and simple. Complex carbohydrates refer to starch and …
Carboxyhemoglobin (CoHb)
A derivative of haemoglobin, also known as carbon monoxide hemoglobin, it is a fairly stable union of carbon monoxide with haemoglobin instead of oxygen or carbon dioxide. It has a much higher affinity for hemoglobin than oxygen, and at high levels impairs the normal transport of oxygen by the blood. The normal value of CoHb …
Canon of parsimony
Generally considered to be a special case of Ockham’s razor in its application to animal or comparative psychology made by C. Lloyd Morgan (1852-1936) in his Introduction to comparative psychology (1894). Prior to Morgan, Wilhelm Wundt (1832-1920) put forward a similar idea in his Lectures on human and animal psychology (1863). The canon is summarised …
Calcarine sulcus (or fissure)
Discovered and named by Thomas H. Huxley (1825-1895) in 1861 during his pursuit of the ‘hippocampus minor’ in non-human primates, it is a sulcus located in layer VI of the occipital lobe that begins under the posterior end of the corpus callosum and arches to the occipital pole. The visual cortex is arranged around this …