Where does isolation collide?

The set of biological barriers that stop two populations or species from interbreeding and exchanging genes, so that they diverge and become distinct: these barriers act before mating or fertilisation, through differences in habitat, timing, courtship, or gamete compatibility, or after it, through hybrids that are inviable or sterile. Coyne and Orr's 1998 The evolutionary genetics of speciation reviewed how such barriers accumulate and how they drive the origin of species. The referent here is a barrier to breeding between living populations, tracked as reduced gene flow, and it has nothing to do with a person cut off from company, concurrent transactions kept from interfering, or a machine shielded from vibration.[1]

Unit

One reproductive barrier between populations, scaled by how much it cuts gene flow

Recovery means

Not applicable

Measured by

Estimated from the strength of premating and postmating barriers and from the gene flow inferred between populations

An objective shortage of social contact and connection: few relationships, infrequent interaction, and a small or thin social network, counted by the presence and frequency of ties rather than by how a person feels. Cornwell and Waite's 2009 Social disconnectedness, perceived isolation, and health among older adults kept this objective disconnectedness apart from the subjective feeling of loneliness and linked both to health. The referent is a countable deficit in one person's social ties, and it is a different thing from a breeding barrier between species, a rule keeping database transactions apart, or the mechanical decoupling of a machine.[2]

Unit

One person's level of social contact, scaled by the number and frequency of ties

Recovery means

Rebuilding contact and network ties can lift it, though the felt loneliness it brings need not follow

Measured by

Assessed with social network inventories counting ties, contact frequency, and group participation, kept distinct from loneliness scales

The guarantee that concurrent database transactions do not interfere with one another, so that each runs as if it had the database to itself: it is the I in the ACID properties, and it is offered in graded strengths called isolation levels, from serializable down to read committed, that trade strictness for speed. Berenson and colleagues' 1995 A critique of ANSI SQL isolation levels showed that the standard definitions of these levels were ambiguous and recast them precisely. The referent is a correctness property of concurrent computation, not a barrier to breeding, a lack of human contact, or the damping of vibration.[3]

Unit

One isolation level, fixing which interferences between concurrent transactions are allowed

Recovery means

Not applicable

Measured by

Specified by which anomalies, such as dirty reads, non-repeatable reads, and phantoms, a level permits, and checked by concurrency tests

The mechanical decoupling of a machine or structure from a source of unwanted vibration, usually by mounting it on springs and dampers so that motion is not passed across the join: a good isolator lets the protected mass ride on its soft mounts while the disturbance runs into them instead. Ibrahim's 2008 Recent advances in nonlinear passive vibration isolators surveyed the devices and theory used to do this over a wide band of frequencies. The referent is the physical interruption of vibration between two bodies, gauged as transmitted force or motion, and it bears no relation to a breeding barrier, a lack of social ties, or a rule about database transactions.[4]

Unit

One isolator between a source and a protected mass, scaled by how much motion it passes on

Recovery means

Not applicable

Measured by

Quantified by transmissibility, the ratio of transmitted to input vibration across a range of frequencies

In Indian philosophy, isolation refers to kaivalya, the goal of Samkhya and Yoga, in which pure consciousness stands isolated from matter. This meaning comes from Burley (2007) in Classical Samkhya and Yoga.[5]

Unit

Recovery means

Measured by