"Scheme" - what is it, definition of the term
Scheme is a minimalist, multi‑paradigm programming language derived from Lisp, distinguished by a compact set of syntactic forms, lexical scoping, first‑class procedures, and a uniform representation of code and data as S‑expressions; it supports functional, imperative, and meta‑programming styles, enforces tail‑call optimization, and provides a powerful macro system that allows developers to extend the language itself, thereby promoting simplicity, composability, and precise reasoning about programs.
Detailed information
The taxonomic framework for acariform and hemipteran parasites groups ticks, true bugs, lice, and fleas into distinct orders and families based on morphological and physiological traits. Ticks belong to the order Ixodida, subdivided into three families: Ixodidae (hard ticks), Argasidae (soft ticks), and Nuttalliellidae (primitive ticks). Distinguishing features include the presence or absence of a scutum, capitulum placement, and feeding apparatus structure.
True bugs that parasitize vertebrates fall within the order Hemiptera, suborder Heteroptera. Within this group, families such as Cimicidae (bed bugs) and Reduviidae (assassin bugs) are relevant. Key diagnostic characters comprise mouthpart type (piercing‑sucking rostrum), wing morphology, and scent gland placement.
Lice are classified under the order Phthiraptera, divided into two suborders: Anoplura (sucking lice) and Mallophaga (chewing lice). Sucking lice possess specialized mouthparts for blood extraction, whereas chewing lice have mandibles adapted for epidermal feeding. Host specificity and body size serve as additional classification criteria.
Fleas are placed in the order Siphonaptera, a monotypic order containing families such as Pulicidae (common flea) and Ceratophyllidae (spiny flea). Defining attributes include laterally compressed bodies, powerful jumping legs, and a siphonate mouthpart for blood intake.
A practical classification approach for these ectoparasites can be summarized as follows:
- Order level: Ixodida, Hemiptera, Phthiraptera, Siphonaptera.
- Family level: Ixodidae, Argasidae, Cimicidae, Anoplura, Mallophaga, Pulicidae.
- Diagnostic traits: body segmentation, mouthpart morphology, presence of scutum or wings, host range.
- Life‑cycle stages: egg, larva/nymph, adult; developmental duration varies among groups.
- Control implications: identification of taxonomic group informs targeted chemical or environmental interventions.
Understanding this systematic arrangement enables precise identification, epidemiological monitoring, and effective management of arthropod infestations affecting humans and animals.