Table 1 Model parameters and their descriptions.

From: Mathematical modeling and analysis of the co-dynamics of crime and drug abuse

Symbol

Intepretation

Range/value

Source

\(\Lambda\)

Recruitment rate

[0.001, 0.1]

Assumed

\(\beta _c\)

Crime diffusion rate

0.0505

32

\(\beta _a\)

Substance abuse diffusion rate

0.0427

2,33

\(\omega\)

The modification parameter

[0, 1]

Assumed

\(\sigma _c\)

Rate of progression to criminal behavior

1/100

Assumed

\(\sigma _a\)

Rate of progression to substance abuse behavior

0.024

23

\(\sigma _e\)

Rate of developing co-occurring behaviors

[1/14, 1/3]

Assumed

\(\theta _{c}\)

Incarceration rate

[0.00016, 0.006]

34

\(\theta _a\)

Substance abused rehabilitation rate

[0.11, 0.13]

35

\(\theta _e\)

Co-engaged rehabilitation rate

[0.00016, 0.13]

34,35

\(\kappa _{c}\)

Recidivism rate of criminals

[0.1, 0.63]

36,37

\(\kappa _a\)

Relapse rate after rehabilitation

[0.4, 0.6]

38,39

\(\kappa _e\)

Co-occurring recidivism rate

[0.1, 0.63]

36,38

\(\phi _c\)

Rehabilitated crime individuals recovery rate

[0.37, 0.9]

36

\(\phi _a\)

Substance rehab recovery rate

[0.4,0.89]

38,39

\(\phi _e\)

Rehabilitated co-engaged individuals recovery rate

[0.1, 0.63]

36,38

\(\gamma _{c}\)

Recovery rate of criminal individuals

[0.37, 0.9]

36

\(\gamma _a\)

Recovery rate of substance -abuse individuals

[1/90, 1/7]

40

\(\gamma _e\)

Recovery rate of co-engaged individuals

[0.37, 0.9]

36,38

\(\tau _{c}\)

Crime resilience rate

[0, 1]

Assumed

\(\tau _a\)

Substance abuse resilience rate

[0, 1]

Assumed

\(\delta _{c}\)

Death rate due to crime

[0.001, 0.1]

41

\(\delta _a\)

Death rate due to substance abuse

[0.001, 0.1]

42

\(\delta _e\)

Death rate due to co-occurring

[0.001, 0.1]

Assumed

\(\mu\)

Natural death rate

[0.001, 0.1]

Assumed