An organism who cells lack organelles and whose DNA is not arranged in chromosomes, but forms a coiled structure called a nucleoid. Prokaryotic organisms are bacteria and blue-green algae. The traditional distinction between prokaryotes and eukaryotes has had to be revised with the discovery of tublin-like, actin-like and histone-like molecules in arch aeons (found, for …
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Progress
Both development and evolution had associated with them the notion of progress (i.e., a process of betterment leading to the achievement of some idealised state). The use of such terms as the development of ‘lower’ and ‘higher’ mental abilities as well as the evolution of ‘lower’ and ‘higher’ organisms contains the assumption of both progress …
Progesterone
It is both an endogenous steroid and a sex hormone. It plays crucial roles in the menstrual cycle and in maintaining the early stages of pregnancy. It is mainly released by the corpus luteum a temporary endocrine gland in the ovaries formed from the empty ovarian follicle after ovulation. During pregnancy, it not only prepares the endometrium (the mucous …
Prognosis
The prediction or forecast of the outcome of any condition, illness or disease; thus whether the person involved will get better, worse or stay the same. See Developmental screening, Diagnosis (or diacrisis), Prediction and explanation, Prediction and retrodiction
Progenitor cells
In short, cells that, by division, generate neuroblasts and gliablasts in nervous system. Also known as a precursor cells, they are regarded as being different from stem cells. While progenitor cells are descendants of stem cells, they differ in that they are more constrained in the ability to differentiate or to renew themselves. Moreover, stem …
Processing units
The units in a connectionist model. A processing unit normally receives input from other units and/or from the environment. Depending on the magnitude of this input and on the activation function of the processing unit (e.g., a threshold function), it can itself become active. In this way, a processing unit shares basic properties with biological …
Prodiction and retrodiction
In prodiction, the explanandum describes an event posterior to at least one of the particular circumstance sentences (I to In) of the explanans. When the explanandum describes an event temporally antecedent to any events given by particular so-called circumstance sentences in the explanans, then we are dealing with retrodiction. Longitudinal (prospective) research, in which the …
Procedure
A set of prescriptions for controlling relevant factors dictated by a particular method and theory, and which include how a particular technique should be used, See Method, Paradigm, Technique, Theory
Process
Description of how a system changes its spatial or temporal organization or both over time. Consequently, it says nothing directly about the mechanism or mechanisms of change (e.g., in ontogenetic development). In dynamical systems terms, such a descriptor is referred to as an order parameter. See Behavior mechanism, Biology, Child psychology, Cognitive psychology, Description, Developmental …
Problem solving
Broadly speaking, it can be conceptualised as coping, sometimes interaction with others, with some environmental challenge, often involving objects, and sometimes in conjunction with others, with an end point in view. Problem solving has two associated features. One is problem finding involving insights into what is missing in terms of arriving at a solution and …