The Bell-LaPadula model restriction that a subject operating at its current level reads only at or below that level and writes only at or above it. An access combining both operations therefore requires equal levels. Safe changes of current level must also control retained information.

Historical name particularly associated with locally destructive basal cell carcinoma.

An infection of deeper skin and subcutaneous tissues producing spreading inflammation. It differs from a localized abscess, although both can coexist.

A deep, coalescent infection of adjacent hair follicles, distinguished from a single superficial pustule. The label alone does not identify the organism or establish an actual patient’s findings.

An infection caused by toxin-producing strains of diphtheria-associated bacteria, classically involving a pharyngeal membrane. Toxin can also damage distant organs, connecting a local source with systemic effects.^[ref]

A bacterium associated with peptic ulcer disease.

The bacterial cause of typhoid fever.

The bacterial species associated with tuberculosis. Bulk lesion chemistry does not by itself establish its presence.

Staphylococcus aureus is a bacterium whose spherical cells commonly form clusters. It can colonize host surfaces without immediately producing disease, while particular strains and circumstances permit infection. Colonization, invasion and toxin action therefore require separate evidence.

Clostridium tetani is an anaerobic, spore-forming bacterium that produces the toxin responsible for tetanus. Local growth and the remote effects of the toxin are distinct parts of the disease mechanism.^[ref]

Historical grouping of minute moving elongated or sinuous organisms; not coextensive with the modern genus Vibrio.

Vibrio is a genus of aquatic bacteria, commonly with curved cells and motility. Vibrio cholerae is a medically important member. The genus includes organisms with different ecological associations and does not imply that every member causes cholera.

Treponema pallidum is a spiral-shaped bacterium associated with syphilis. Its interaction with a host involves multiple tissues and stages; the organism, the resulting infection and a particular clinical manifestation are different concepts.^[ref]

Vibrio cholerae is a species of Vibrio. Toxin-producing strains cause cholera, but species identity and toxin production are separate properties. Connecting an isolate to disease therefore requires more than its curved cell shape.

A group of bacteria capable of oxidative production of acetic acid from ethanol; particular cultures can contain several species.

Streptococcus is a genus of bacteria whose spherical cells commonly occur in chains. Its species differ in host association and pathogenicity, so a genus name alone does not identify one disease or physiological role.

The nullclines meet at the origin and $P=(2-k,k(2-k))$. At the origin, the Jacobian matrix has trace three, determinant $2-k>0$ and discriminant $1+4k>0$, giving an unstable node. At $P$, its determinant is $k-2<0$, giving a saddle equilibrium. The horizontal component is positive below the parabolic nullcline and negative above it; the vertical component is positive above the straight nullcline and negative below it. These signs determine the directional regions of the phase portrait.

The quadrant is not positively invariant: nonzero points on either axis have an outward-pointing component. Restricting a drawing to that quadrant does not keep its trajectories there. For $k>2$, only the saddle at the origin remains in the quadrant, and an exponential Dulac multiplier for a quadratic planar system excludes nonconstant periodic orbits there.

An autonomic nerve carries fibers involved in regulation of internal organs, glands or vascular targets through the autonomic nervous system. A named peripheral nerve can contain autonomic fibers together with sensory or somatic motor components. The fiber’s function and its anatomical route are different classifications.

A strange attractor, in the geometric convention, is an attractor whose structure is irregular or fractal rather than a smooth point, cycle or torus. The geometry concerns the set of possible long-term states. Chaos concerns evolution on that set. Some authors include chaos in the meaning of strange, so the convention must be stated.

The separation matters because the same plot cannot answer every question. A box-counting dimension calculation asks how many boxes are needed to cover a set as their size decreases. A Lyapunov exponent calculation follows the growth of a perturbation along a trajectory. These measure different features, and neither number can be substituted for the other.

Strange nonchaotic attractors provide the explicit warning: geometrically complicated attraction can occur without a positive Lyapunov exponent. The original construction used systems driven by two incommensurate frequencies.^[ref] Thus fractal-looking geometry alone is insufficient evidence for a chosen definition of chaos.

Attraction in a dynamical system means convergence of nearby forward trajectories toward a specified invariant state or set. Attraction and Lyapunov stability are separate properties; together they give the usual local asymptotic stability of an equilibrium.